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  • 1.
    Berglund, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Miniature Plasma Sources for High-Precision Molecular Spectroscopy in Planetary Exploration2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The prospect of finding life outside Earth has fascinated mankind for ages, and new technology continuously pushes the boundary of how remote and how obscure evidence we can find. Employing smaller, or completely new, types of landers and robots, and equipping them with miniature instruments would indeed revolutionize exploration of other planets and moons.

    In this thesis, microsystems technology is used to create a miniature high-precision isotope-resolving molecular spectrometer utilizing the optogalvanic effect. The heart of the instrument, as well as this thesis, is a microplasma source.

    The plasma source is a split-ring resonator, chosen for its simplicity, pressure range and easily accessible plasma, and modified to fit the challenging application, e.g., by the adding of an additional ground plane for improved electromagnetic shielding, and the integration of microscopic plasma probes to extract the pristine optogalvanic signal.

    Plasma sources of this kind have been manufactured in both printed circuit board and alumina, the latter for its chemical inertness and for compatibility with other devices in a total analysis system. From previous studies, classical optogalvanic spectroscopy (OGS), although being very sensitive, is known to suffer from stability and reproducibility issues. In this thesis several studies were conducted to investigate and improve these shortcomings, and to improve the signal-to-noise ratio. Moreover, extensive work was put into understanding the underlying physics of the technique.

    The plasma sources developed here, are the first ever miniature devices to be used in OGS, and exhibits several benefits compared to traditional solutions. Furthermore, it has been confirmed that OGS scales well with miniaturization. For example, the signal strength does not decrease as the volume is reduced like in regular absorption spectroscopy. Moreover, the stability and reproducibility are greatly increased, in some cases as much as by two orders of magnitude, compared with recent studies made on a classical OGS setup. The signal-to-noise ratio has also been greatly improved, e.g., by enclosing the sample cell and by biasing the plasma. Another benefit of a miniature sample cell is the miniscule amount of sample it requires, which can be important in many applications where only small amounts of sample are available.

    To conclude: With this work, an important step toward a miniature, yet highly performing, instrument for detection of extraterrestrial life, has been taken.

    List of papers
    1. Operation characteristics and optical emission distribution of a miniaturized silicon through-substrate split-ring resonator microplasma source
    Open this publication in new window or tab >>Operation characteristics and optical emission distribution of a miniaturized silicon through-substrate split-ring resonator microplasma source
    2014 (English)In: Journal of microelectromechanical systems, ISSN 1057-7157, E-ISSN 1941-0158, Vol. 23, no 6, p. 1340-1345Article in journal (Refereed) Published
    Abstract [en]

    There are many new microplasma sources being developed for a wide variety of applications, each with different properties tailored to its specific use. Microplasma sources enable portable instruments for, e.g., chemical analysis, sterilization, or activation of substances. A novel microplasma source, based on a microstrip split-ring resonator design with electrodes integrated in its silicon substrate, was designed, manufactured, and evaluated. This device has a plasma discharge gap with a controlled volume and geometry, and offers straightforward integration with other microelectromechancial systems (MEMS) components, e.g., microfluidics. The realized device was resonant at around 2.9 GHz with a quality factor of 18.7. Two different operational modes were observed with the plasma at high pressure being confined in the gap between the electrodes, whereas the plasma at low pressures appeared between the ends of the electrodes on the backside. Measurement of the angular distribution of light emitted from the device with through-substrate electrodes showed narrow emission lobes compared with a reference plasma source with on-substrate electrodes.

    National Category
    Physical Sciences Engineering and Technology
    Identifiers
    urn:nbn:se:uu:diva-239111 (URN)10.1109/JMEMS.2014.2312849 (DOI)000345851100010 ()
    Available from: 2015-01-05 Created: 2014-12-18 Last updated: 2017-12-05Bibliographically approved
    2. Evaluation of a microplasma source based on a stripline split-ring resonator
    Open this publication in new window or tab >>Evaluation of a microplasma source based on a stripline split-ring resonator
    2013 (English)In: Plasma sources science & technology (Print), ISSN 0963-0252, E-ISSN 1361-6595, Vol. 22, no 5, p. 055017-Article in journal (Refereed) Published
    Abstract [en]

    In this paper, a stripline split-ring resonator microwave-induced plasma source, aimed for integration in complex systems, is presented and compared with a traditional microstrip design. Devices based on the two designs are evaluated using a plasma breakdown test setup for measuring the power required to ignite plasmas at different pressures. Moreover, the radiation efficiency of the devices is investigated with a Wheeler cap, and their electromagnetic compatibility is investigated in a variable electrical environment emulating an application. Finally, the basic properties of the plasma in the two designs are investigated in terms of electron temperature, plasma potential and ion density. The study shows that, with a minor increase in plasma ignition power, the stripline design provides a more isolated and easy-to-integrate alternative to the conventional microstrip design. Moreover, the stripline devices showed a decreased antenna efficiency as compared with their microstrip counterparts, which is beneficial for plasma sources. Furthermore, the investigated stripline devices exhibited virtually no frequency shift in a varying electromagnetic environment, whereas the resonance frequency of their microstrip counterparts shifted up to 17.5%. With regard to the plasma parameters, the different designs showed only minor differences in electron temperature, whereas the ion density was higher with the stripline design.

    Place, publisher, year, edition, pages
    Institute of Physics (IOP), 2013
    Keywords
    Split-ring resonator, Microwave plasma, Microstrip, Stripline, Plasma, Wheeler cap, Langmuir probe
    National Category
    Other Physics Topics Engineering and Technology
    Research subject
    Engineering Science with specialization in Microsystems Technology; Engineering Science with specialization in Microwave Technology
    Identifiers
    urn:nbn:se:uu:diva-206792 (URN)10.1088/0963-0252/22/5/055017 (DOI)000325246400017 ()
    Available from: 2013-09-04 Created: 2013-09-04 Last updated: 2017-12-06Bibliographically approved
    3. Microplasma source for optogalvanic spectroscopy of nanogram samples
    Open this publication in new window or tab >>Microplasma source for optogalvanic spectroscopy of nanogram samples
    2013 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 114, no 3, p. 033302-Article in journal (Refereed) Published
    Abstract [en]

    The demand for analysis of smaller samples in isotopic ratio measurements of rare isotopes is continuously rising with the development of new applications, particularly in biomedicine. Interesting in this aspect are methods based on optogalvanic spectroscopy, which have been reported to facilitate both 13C-to-12C and 14C-to-12C ratio measurements with high sensitivity. These methods also facilitate analysis of very small samples, down to the microgram range, which makes them very competitive to other technologies, e.g., accelerator mass spectroscopy. However, there exists a demand for moving beyond the microgram range, especially from regenerative medicine, where samples consist of, e.g., DNA, and, hence, the total sample amount is extremely small. Making optogalvanic spectroscopy of carbon isotopes applicable to such small samples, requires miniaturization of the key component of the system, namely the plasma source, in which the sample is ionized before analysis. In this paper, a novel design of such a microplasma source based on a stripline split-ring resonator is presented and evaluated in a basic optogalvanic spectrometer. The investigations focus on the capability of the plasma source to measure the optogalvanic signal in general, and the effect of different system and device specific parameters on the amplitude and stability of the optogalvanic signal in particular. Different sources of noise and instabilities are identified, and methods of mitigating these issues are discussed. Finally, the ability of the cell to handle analysis of samples down to the nanogram range is investigated, pinpointing the great prospects of stripline split-ring resonators in optogalvanic spectroscopy.

    Place, publisher, year, edition, pages
    American Institute of Physics (AIP), 2013
    Keywords
    nanostructured materials, optogalvanic spectroscopy, plasma instability, plasma probes, plasma sources, strip line resonators
    National Category
    Other Physics Topics Engineering and Technology
    Research subject
    Engineering Science with specialization in Microsystems Technology; Engineering Science with specialization in Ion Physics; Engineering Science with specialization in Microwave Technology
    Identifiers
    urn:nbn:se:uu:diva-204156 (URN)10.1063/1.4813414 (DOI)000322202700014 ()
    Available from: 2013-07-22 Created: 2013-07-22 Last updated: 2017-12-06Bibliographically approved
    4. Stripline split-ring resonator with integrated optogalvanic sample cell
    Open this publication in new window or tab >>Stripline split-ring resonator with integrated optogalvanic sample cell
    Show others...
    2014 (English)In: Laser Physics Letters, ISSN 1612-2011, Vol. 11, no 4, p. 045701-Article in journal, Letter (Refereed) Published
    Abstract [en]

    Intracavity optogalvanic spectroscopy (ICOGS) has been proposed as a method for unambiguous detection of rare isotopes. Of particular interest is 14C, where detection of extremely low concentrations in the 1:1015 range (14C:12C), is of interest in, e.g., radiocarbon dating and pharmaceutical sciences. However, recent reports show that ICOGS suffers from substantial problems with reproducibility. To qualify ICOGS as an analytical method, more stable and reliable plasma generation and signal detection are needed. In our proposed setup, critical parameters have been improved. We have utilized a stripline split-ring resonator microwave-induced microplasma source to excite and sustain the plasma. Such a microplasma source offers several advantages over conventional ICOGS plasma sources. For example, the stripline split-ring resonator concept employs separated plasma generation and signal detection, which enables sensitive detection at stable plasma conditions. The concept also permits in situ observation of the discharge conditions, which was found to improve reproducibility. Unique to the stripline split-ring resonator microplasma source of in this study, is that the optogalvanic sample cell has been embedded in the device itself. This integration enabled improved temperature control and more stable and accurate signal detection. Significant improvements are demonstrated, including reproducibility, signal-to-noise ratio and precision.

    Place, publisher, year, edition, pages
    Institute of Physics (IOP), 2014
    Keywords
    Optogalvanic spectroscopy, Laser-assisted ratio analyzer, Split-ring resonator, microwave-induced microplasma source
    National Category
    Atom and Molecular Physics and Optics Fusion, Plasma and Space Physics Other Materials Engineering
    Research subject
    Physics; Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-218769 (URN)10.1088/1612-2011/11/4/045701 (DOI)000332768800011 ()
    Funder
    Swedish Research Council, A0442201
    Available from: 2014-02-17 Created: 2014-02-17 Last updated: 2015-05-12Bibliographically approved
    5. Improved optogalvanic detection with voltage biased Langmuir probes
    Open this publication in new window or tab >>Improved optogalvanic detection with voltage biased Langmuir probes
    2014 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 116, no 24, p. 243301-Article in journal (Refereed) Published
    Abstract [en]

    Optogalvanic detectors show great potential for infrared spectroscopy, especially in cavity enhanced techniques where they, in contrast to ordinary absorption detectors, can perform intracavity measurements. This enables them to utilize the signal-to-noise ratio improvement gained from the extended effective path length inside an optical cavity, without losing signal strength due to the limited amount of light exiting through the rear mirror. However, if optogalvanic detectors are to become truly competitive, their intrinsic sensitivity and stability has to be improved. This, in turn, requires a better understanding of the mechanisms behind the generation of the optogalvanic signal. The study presented here focuses on an optogalvanic detector based on a miniaturized stripline split-ring resonator plasma source equipped with Langmuir probes for detecting the optogalvanic signal. In particular, the effect of applying a constant bias voltage to one of the probes is investigated, both with respect to the sensitivity and stability, and to the mechanism behind the generation of the signal. Experiments with different bias voltages at different pressures and gas composition have been conducted. In particular, two different gas compositions (pure CO2 and 0.25% CO2 in 99.75% N-2) at six different pressures (100 Pa to 600 Pa) have been studied. It has been shown that probe biasing effectively improves the performance of the detector, by increasing the amplitude of the signal linearly over one order of magnitude, and the stability by about 40% compared with previous studies. Furthermore, it has been shown that relatively straightforward plasma theory can be applied to interpret the mechanism behind the generation of the signal, although additional mechanisms, such as rovibrational excitation from electron-molecule collisions, become apparent in CO2 plasmas with electron energies in the 1-6 eV range. With the achieved performance improvement and the more solid theoretical framework presented here, stripline split-ring resonator optogalvanic detectors can evolve into a compact, inexpensive, and easy-to-operate alternative for future infrared spectrometers. (C) 2014 AIP Publishing LLC.

    National Category
    Physical Sciences
    Identifiers
    urn:nbn:se:uu:diva-242865 (URN)10.1063/1.4904964 (DOI)000347164300003 ()
    Available from: 2015-02-04 Created: 2015-02-02 Last updated: 2017-12-05Bibliographically approved
    6. Evaluation of dielectric properties of HTCC alumina for realization of plasma sources
    Open this publication in new window or tab >>Evaluation of dielectric properties of HTCC alumina for realization of plasma sources
    2015 (English)In: Journal of Electronic Materials, ISSN 0361-5235, E-ISSN 1543-186X, Vol. 44, no 10, p. 3654-3660Article in journal (Refereed) Published
    Abstract [en]

    As the sensitivity of optogalvanic spectroscopy based on prototype microplasma sources increases, contamination from composite materials in the printed circuit board used starts to become a concern. In this paper, a transfer to high-temperature cofired alumina and platinum is made and evaluated. The high-purity alumina provides an inert plasma environment, and allows for temperatures above 1000A degrees C, which is beneficial for future integration of a combustor. To facilitate the design of high-end plasma sources, characterization of the radio frequency (RF) parameters of the materials around 2.6 GHz is carried out. A RF resonator structure was fabricated in both microstrip and stripline configurations. These resonators were geometrically and electrically characterized, and epsilon (r) and tan were calculated using the RF waveguide design tool Wcalc. The resulting epsilon (r) for the microstrip and stripline was found to be 10.68 (+/- 0.12) and 9.65 (+/- 0.14), respectively. The average tan of all devices was found to be 0.0011 (+/- 0.0007). With these parameters, a series of proof-of-concept plasma sources were fabricated and evaluated. Some problems in the fabrication stemmed from the lamination and difficulties with the screen-printing, but a functioning plasma source was demonstrated.

    National Category
    Ceramics Engineering and Technology Physical Sciences
    Research subject
    Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-251300 (URN)10.1007/s11664-015-3901-7 (DOI)000360672900061 ()
    Funder
    Swedish National Space BoardKnut and Alice Wallenberg Foundation
    Available from: 2015-04-15 Created: 2015-04-15 Last updated: 2017-12-04Bibliographically approved
    7. Manufacturing Miniature Langmuir probes by Fusing Platinum Bond Wires
    Open this publication in new window or tab >>Manufacturing Miniature Langmuir probes by Fusing Platinum Bond Wires
    2015 (English)In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 25, no 10, article id 105012Article in journal (Refereed) Published
    Abstract [en]

    This paper reports on a novel method for manufacturing microscopic Langmuir probes with spherical tips from platinum bond wires for plasma characterization in microplasma sources by fusing. Here, the resulting endpoints, formed by droplets of a fused wire, are intended to act as a spherical Langmuir probe. For studying the fusing behavior, bond wires were wedge-bonded over a 2 mm wide slit, to emulate the final application, and fused at different currents and voltages. For electrical isolation, a set of wires were coated with a 4 µm thick layer of Parylene before they were fused. After fusing, the gap size, as well as the shape and area of the ends of the remaining stubs were measured. The yield of the process was also investigated, and the fusing event was studied using a high-speed camera for analyzing the dynamics of fusing. Four characteristic tip shapes were observed: spherical, semi-spherical, serpentine shaped and folded. The stub length leveled out at ~420µm. The fusing of the coated wires required a higher power for attaining a spherical shape. Finally, a Parylene coated bond wire was integrated into a stripline split-ring resonator (SSRR) microplasma source, and fused to form two Langmuir probes with spherical endpoints. These probes were used for measuring the I-V characteristics of a plasma generated by the SSRR. In a voltage range between -60 V and 60 V, the fused stubs exhibited the expected behavior of spherical Langmuir probes and will be considered for future integration.

    Keywords
    Langmuir probe; bond wire; fusing; microplasma source
    National Category
    Physical Sciences Engineering and Technology
    Research subject
    Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-251306 (URN)10.1088/0960-1317/25/10/105012 (DOI)000366827400028 ()
    Funder
    Swedish National Space BoardKnut and Alice Wallenberg Foundation
    Available from: 2015-04-15 Created: 2015-04-15 Last updated: 2018-08-03Bibliographically approved
  • 2.
    Berglund, Martin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Khaji, Zahra
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Persson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Sturesson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC). Swedish Def Univ, Dept Mil Studies, Stockholm, Sweden.
    Söderberg Breivik, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Extreme-temperature lab on a chip for optogalvanic spectroscopy of ultra small samples – key components and a first integration attempt2016In: 27th Micromechanics And Microsystems Europe Workshop (MME 2016) / [ed] IOP, Institute of Physics (IOP), 2016, Vol. 757, article id 012029Conference paper (Refereed)
    Abstract [en]

    This is a short summary of the authors’ recent R&D on valves, combustors, plasma sources, and pressure and temperature sensors, realized in high-temperature co-fired ceramics, and an account for the first attempt to monolithically integrate them to form a lab on a chip for sample administration, preparation and analysis, as a stage in optogalvanic spectroscopy.

  • 3.
    Blomqvist, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Construction and evaluation of a magnetoresistive ground penetrating radar system2011Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This Master Thesis examines the possibility to apply a magnetometer developed by the Ångstöm space technology center to a small magnetic ground penetrating radar system with dimension in the order of one dm³. The magnetometer is broadband (DC-1GHz) and miniaturized. Loop antennas are used to transmit the signal.

       A series of experiments have been performed in order to characterize the system, mainly examining the ability to determine distance to a target, using continuous sine wave signals and pulse trains. Standing wave patterns are formed between antenna and target and can be used for determining distance in the continuous case. When using a pulse train, the echo from the target could not be resolved using the current experiment set up, distance could therefore not be determined.

  • 4.
    Halvarsson, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Ett kommunikationssystem för fiberoptisk överföring av bilddata förvärvad av en miniatyriserad undervattensfarkost2011Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report describes the development and implementation of a system for transmitting digital information at high speeds from a miniaturized submersible developed by the Ångström Space Technology Centre at Uppsala University. For instance, the vehicle shall transmit image data – even stream live video - through an optical fibre to a monitor in a ground station. Hence, the system shall be used both to convert the image data to make it transmittable, and to recreate it at the receiver.

    The work includes a pre-study of the programming language and the technology used. A concept for the solution is presented together with main components later broken down into internal functions. Following on this, other components that were necessary for fulfilling the function of the main components were identified. The system was developed with the hardware description language VHDL in order to be implementable and testable on an FPGA platform, but also to be transferable to other devices.

    After the development and implementation on the hardware platform, the system was tested and verified. Analysis showed that some modifications were required to produce the desired results. These modifications implied some deviations from the assignment statement but gave rise to suggestions for further improvement of the concept. All in all, however, the solution was successfully verified since the transmitted data was possible to recreate the original image.

    The report contains drawings of the developed system and the source code it consists of.

  • 5.
    Jonsson, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Microsystems Technology for Underwater Vehicle Applications2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The aim of this thesis work has been to investigate how miniaturization, such as microsystems technology, can potentially increase the scientific throughput in exploration of hard-to-reach underwater environments, such as the subglacial lakes of Antarctica, or other challenging environments, including cave systems and wrecks. A number of instruments and subsystems applicable to miniature submersibles have been developed and studied, and their potential to provide a high functionality density for size-restricted exploration platforms has been assessed.

    To provide an onboard camera system with measurement capabilities, simulation and design tools for diffractive optics were developed, and microoptics realized to project reference patterns onto objects to reveal their topography. The influence of murky water on the measurement accuracy was also studied.

    For longer-range mapping of the surroundings, and under conditions with even less visibility, the performance of a very small, high-frequency side-scanning sonar was investigated using extensive modeling and physical testing. In particular, the interference on the acoustic beam from tight mounting in a hull was investigated. A range in excess of 30 m and centimeter resolution were obtained.

    Besides these systems, which can be used to navigate and map environments, a two-dimensional, thermal sensor for minute flows was developed. Measuring speed and direction of water flows, this sensor can aid in the general classification of the environment and also monitor the submersible’s movement. As the flow of waters in subglacial lakes is estimated to be minute, the detection limit and sensitivity were investigated.

    Measurements of water properties are facilitated by the chip-based conductivity, temperature, and depth sensor system developed. Macroscopically, this is an essential oceanographic instrument with which salinity is determined. Contrary to what was expected, MHz frequencies proved to be advantageous for conductivity measurements.

    Finally, sampling of water using an acoustically enriching microdevice, and even enabling return of pristine samples via the use of integrated latchable, high-pressure valves, was realized and evaluated. Particularly, investigations of the device’s ability to capture and hold on to microorganisms, were conducted.

    Further developed and studied, these devices – as subsystems to miniature submersibles, or as stand-alone instruments – should enable exploration of previously unreachable submerged environments.

    List of papers
    1. Simulation, manufacturing, and evaluation of a sonar for a miniaturized submersible explorer
    Open this publication in new window or tab >>Simulation, manufacturing, and evaluation of a sonar for a miniaturized submersible explorer
    Show others...
    2010 (English)In: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, ISSN 0885-3010, E-ISSN 1525-8955, Vol. 57, no 2, p. 490-495Article in journal (Refereed) Published
    Abstract [en]

    Single-beam side-scan sonar elements, to be fitted on a miniaturized submersible, are here simulated, manufactured, and evaluated. Finite element analysis simulations are compared with measurements, and an overall observation is that the agreement between simulations and measurements deviates from the measured values of 1.5 to 2°, for the narrow lobe angle, by less than 10% for most models. An overall finding is that the lobe width along the track direction can be accurately simulated and, hence, the resolution of the sonars can be predicted. This paper presents, to the authors’ knowledge, the world’s smallest side-scan sonars.

    Keywords
    Sonar, beam width, acoustic imaging
    National Category
    Fluid Mechanics and Acoustics
    Research subject
    Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-121440 (URN)10.1109/TUFFC.2010.1429 (DOI)000274817300023 ()
    Projects
    Deeper Access, Deeper Understanding (DADU)
    Note

    This article is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, this work may not be reposted without the explicit permission of the copyright holder.

    Available from: 2010-03-23 Created: 2010-03-23 Last updated: 2017-12-12Bibliographically approved
    2. Enclosure-Induced Interference Effects in a Miniaturized Sidescan Sonar
    Open this publication in new window or tab >>Enclosure-Induced Interference Effects in a Miniaturized Sidescan Sonar
    Show others...
    2012 (English)In: IEEE Journal of Oceanic Engineering, ISSN 0364-9059, E-ISSN 1558-1691, Vol. 37, no 2, p. 236-243Article in journal (Refereed) Published
    Abstract [en]

    On, for instance, the miniaturized submersible explorer, Deeper Access, Deeper Understanding (DADU), only 20 cm in length and 5 cm in diameter, the sidescan sonar needs to be tightly mounted in the hull. Finite element analysis (FEA) as well as physical measurements were used to investigate the effects of beam interaction with acoustically nearby rigid boundaries. Computer simulations showed the first major dip in the beam shape to vary in strength, size, and position with the enclosure wall height, from a position of 47° at 0.0-mm wall height to 32° at 3.0-mm wall height. Hydrophonic measurements on the manufactured test device confirmed these values to within 9%, varying between 47° and 29°. In addition, Schlieren imaging was proposed and used as a noninvasive means of qualitative beam shape characterization. A field test was performed with the enclosure height set to 0 and 3 mm. With the latter height, a dark band, corresponding to a sonar sensitivity dip at about 30° in the beam, appeared in the sonar image. It was found that the beam shape is sensitive to small mounting errors, in this case where the wavelength of the sonar is on the same size scale as the enclosure. Furthermore, it was found that FEA models can be used to accurately predict enclosure effects on sonar beam shapes, and Schlieren imaging can be used to visually detect the shape deformations in mounted sonar devices.

    Keywords
    Beam shape, finite element analysis (FEA), miniaturize, Schlieren, sidescan sonar
    National Category
    Fluid Mechanics and Acoustics
    Research subject
    Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-171730 (URN)10.1109/JOE.2012.2188160 (DOI)000303326500007 ()
    Projects
    Deeper Access, Deeper Understanding (DADU)
    Available from: 2012-03-26 Created: 2012-03-26 Last updated: 2017-12-07Bibliographically approved
    3. A compact system to extract topography information from scenes viewed by a miniaturized submersible explorer
    Open this publication in new window or tab >>A compact system to extract topography information from scenes viewed by a miniaturized submersible explorer
    Show others...
    2012 (English)In: Sensors and Actuators A-Physical, ISSN 0924-4247, E-ISSN 1873-3069, Vol. 188, no SI, p. 401-410Article in journal, Meeting abstract (Refereed) Published
    Abstract [en]

    In images taken underwater, it is generally difficult to correctly extract distances and geometric informationof objects. Different techniques, collectively referred to as photogrammetry, exist to measurefeatures in images. One of these is to project a reference pattern onto an object in a scene viewed by acamera, and register the distortion of this pattern, to calculate the shape of, and distance to, that object.This method is implemented here on a miniaturized submersible explorer equipped with, among manyother instruments, a camera. Diffractive optical elements (DOEs) have been designed and manufacturedusing microsystems technology, to, together with a laser diode, camera, and in-house developed software,provide a compact system for projecting reference patterns and analyzing their deformations. Thesystem has been characterized by measuring the distances and angles of objects in a water tank, andattempting to reproduce their shapes. The range of operation of the system, verified to be at least onemeter, is limited by the compact mounting in the small submersible and the cameras’ performance.The system was found to work well under turbid conditions as well as in water containing larger particles.Together with a vehicle-mounted camera, the compact and low-power DOE laser projection systemenables topographical measurement.

    Keywords
    Photogrammetry, Diffractive, Laser, Underwater, Images, Miniaturized
    National Category
    Engineering and Technology
    Research subject
    Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-171732 (URN)10.1016/j.sna.2012.02.034 (DOI)000312692500054 ()
    Conference
    The 16th International Conference on Solid-State Sensors, Actuators and Microsystems, 5-9 June, 2011, Beijing, CHINA
    Projects
    Deeper Access, Deeper Understanding (DADU)
    Available from: 2012-03-26 Created: 2012-03-26 Last updated: 2017-12-07Bibliographically approved
    4. Acoustically enriching, large-depth aquatic sampler
    Open this publication in new window or tab >>Acoustically enriching, large-depth aquatic sampler
    Show others...
    2012 (English)In: Lab on a Chip, ISSN 1473-0197, E-ISSN 1473-0189, Vol. 12, no 9, p. 1619-1628Article in journal (Refereed) Published
    Abstract [en]

    In marine biology, it is useful to collect water samples when exploring the distribution and diversity of microbial communities in underwater environments. In order to provide, e.g., a miniaturized submersible explorer with the capability of collecting microorganisms, a compact sample enrichment system has been developed. The sampler is 30 mm long, 15 mm wide, and just a few millimetres thick. Integrated in a multilayer steel, polyimide and glass construction is a microfluidic channel with piezoelectric transducers, where microorganism and particle samples are collected and enriched, using acoustic radiation forces for gentle and labelless trapping. High-pressure, latchable valves, using paraffin as the actuation material, at each end of the microfluidic channel keep the collected sample pristine. A funnel structure raised above the surface of the device directs water into the microfluidic channel as the vehicle propels itself or when there is a flow across its hull. The valves proved leak proof to a pressure of 2.1 MPa for 19 hours and momentary pressures of 12.5 MPa, corresponding to an ocean depth of more than 1200 metres. By reactivating the latching mechanism, small leakages through the valves could be remedied, which could thus increase the leak-less operational time. Fluorescent particles, 1.9 µm in diameter, were successfully trapped in the microfluidic channel at flow rates up to 15 ml min-1, corresponding to an 18.5 cm s-1 external flow rate of the sampler. In addition, liquid-suspended GFP-marked yeast cells were successfully trapped.

    Keywords
    Acoustic, microorganism, enriching, trap, valve, paraffin, sampler, marine, actuator
    National Category
    Engineering and Technology
    Research subject
    Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-171734 (URN)10.1039/C2LC00025C (DOI)000302368200009 ()
    Projects
    Deeper Access, Deeper Understanding (DADU)
    Available from: 2012-03-26 Created: 2012-03-26 Last updated: 2017-12-07Bibliographically approved
    5. A latchable high-pressure thermohydraulic valve actuator
    Open this publication in new window or tab >>A latchable high-pressure thermohydraulic valve actuator
    2012 (English)In: Sensors and Actuators A-Physical, ISSN 0924-4247, E-ISSN 1873-3069, Vol. 188, p. 292-297Article in journal (Refereed) Published
    Abstract [en]

    This work presents a latchable thermohydraulic microactuator for use in high-pressure valves, e.g. for oceanic sampling in missions of long duration. Mounted on a miniature submersible, it can be used in confined spaces to explore previously unreachable environments. However, the device can be used in any high-pressure application where long duration open and/or closed valve states are required, and power consumption is an issue. The actuator is fabricated using standard batch-processes as photochemical machining, wet etching and photolithography. The actuation and latching mechanisms are both thermohydraulic, using solid-to-liquid phase transition of paraffin for actuation and of a low melting point alloy for latching. Focus of this work is on the endurance of the actuator to facilitate a bistable valve. The actuator managed to keep a deflected position for almost 50 hours to the load equivalent to 1.8 MPa applied pressure, after which the experiment was aborted. No pressure dependence was discovered in the latching losses, i.e. the difference in deflection before and after the actuator is powered off. Furthermore, the effect of intermixing of paraffin and the low melting point alloy was evaluated.

    Place, publisher, year, edition, pages
    Elsevier, 2012
    Keywords
    Fluid control, Bistable, Steel, Actuator, Paraffin, Low melting point alloy
    National Category
    Engineering and Technology
    Research subject
    Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-171755 (URN)10.1016/j.sna.2011.11.027 (DOI)000312692500039 ()
    Conference
    The 16th International Conference on Solid-State Sensors, Actuators and Microsystems, 5-9 June, 2011, Beijing, CHINA
    Available from: 2012-03-27 Created: 2012-03-27 Last updated: 2017-12-07Bibliographically approved
    6. Two-Dimensional Thermal Velocity Sensor for Submersible navigation and Minute Flow Measurements
    Open this publication in new window or tab >>Two-Dimensional Thermal Velocity Sensor for Submersible navigation and Minute Flow Measurements
    2013 (English)In: IEEE Sensors Journal, ISSN 1530-437X, E-ISSN 1558-1748, Vol. 13, no 1, p. 359-370Article in journal (Refereed) Published
    Abstract [en]

    A 2-D thermal velocity microsensor for use as a navigational aid and for flow measurements on a miniaturized submersible is developed in this paper. The sensor with nickel heater and temperature sensors on a Pyrex substrate, designed for mounting on the outside of the submersible hull, is fabricated and tested in an application-like environment and proven to be able to measure water speed from zero to 40 mm/s with a power consumption less than 15 mW and determine the flow direction with an error less than ±8°. Finite Element Analysis is used to investigate design and operation parameters and possible biofouling effects on the sensor signal. The effect on shape and orientation of the sensor's mounting surface is also studied.

    National Category
    Other Materials Engineering
    Research subject
    Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-171767 (URN)10.1109/JSEN.2012.2216866 (DOI)000313685400028 ()
    Available from: 2012-03-27 Created: 2012-03-27 Last updated: 2017-12-07Bibliographically approved
    7. Towards chip-based salinity measurements for small submersibles and biologgers
    Open this publication in new window or tab >>Towards chip-based salinity measurements for small submersibles and biologgers
    2013 (English)In: International Journal of Oceanography, ISSN 1687-9406, E-ISSN 1687-9414, Vol. 2013, p. 529674-Article in journal (Refereed) Published
    Abstract [en]

    Water’s salinity plays an important role in the environment. It can be determined by measuring conductivity, temperature, anddepth (CTD). The corresponding sensor systems are commonly large and cumbersome. Here, a 7.5 × 3.5mm chip, containingmicrostructured CTD sensor elements, has been developed. On this, 1.5mm2 gold finger electrodes are used to measure theimpedance, and thereby the conductivity of water, in the MHz frequency range. Operation at these frequencies resulted in highersensitivities than those at sub-MHz frequencies. Up to 14 kΩ per parts per thousand salt concentration was obtained repeatedlyfor freshwater concentrations.This was three orders of magnitude higher than that obtained for concentrations in and above thebrackish range. A platinumelectrode is used to determine a set ambient temperature with an accuracy of 0.005∘C.Membranes withNichrome strain gauges responded to a pressure change of 1 bar with a change in resistance of up to 0.21Ω. A linear fit to data over7 bars gave a sensitivity of 0.1185Ω/bar with an R2 of 0.9964. This indicates that the described device can be used in size-limitedapplications, like miniaturized submersibles, or as a bio-logger on marine animals.

    Place, publisher, year, edition, pages
    Hindawi Publishing Corporation, 2013
    Keywords
    Conductivity, Temperature, Depth, CTD, Pressure, Marine, thin film, micro
    National Category
    Engineering and Technology
    Research subject
    Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-171740 (URN)10.1155/2013/529674 (DOI)
    Projects
    Deeper Access, Deeper Understanding (DADU)
    Funder
    Mistra - The Swedish Foundation for Strategic Environmental Research
    Available from: 2012-03-27 Created: 2012-03-27 Last updated: 2017-12-07Bibliographically approved
  • 6.
    Khaji, Zahra
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Barbade, Dhananjay
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Palmer, Kristoffer
    SSC Nanospace.
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Alumina-based monopropellant microthruster with integrated heater, catalytic bed and temperature sensors2016In: 27th Micromechanics And Microsystems Europe Workshop (Mme 2016) / [ed] IOP, Institute of Physics (IOP), 2016, Vol. 757, article id 012025Conference paper (Refereed)
    Abstract [en]

    A liquid propellant alumina microthruster with an integrated heater, catalytic bed and two temperature sensors has been developed and tested using 30 wt. % hydrogen peroxide. The temperature sensors and the catalytic bed were screen-printed using platinum paste on tapes of alumina that was stacked and laminated before sintering. In order to increase the surface of the catalytic bed, the platinum paste was mixed with a sacrificial paste that disappeared during sintering, leaving behind a porous and rough layer. Complete evaporation and combustion, resulting in only gas coming from the outlet, was achieved with powers above 3.7 W for a propellant flow of 50 μl/min. At this power, the catalytic bed reached a maximum temperature of 147°C. The component was successfully operated up to a temperature of 307°C, where it cracked.

  • 7.
    Khaji, Zahra
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Barbade, Dhananjay
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Palmer, Kristoffer
    SSC Nanospace.
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Endurance and Failure of an Alumina-based Monopropellant Microthruster with Integrated Heater, Catalytic Bed and Temperature Sensors2017In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 27, no 5, p. 1-11, article id 055011Article in journal (Refereed)
    Abstract [en]

    Monopropellant ceramic microthrusters with an integrated heater, catalytic bed and two temperature sensors, but of various designs, were manufactured by milling a fluidic channel and chamber, and a nozzle, and screen printing platinum patterns on green tapes of alumina that were stacked and laminated before sintering. In order to increase the surface area of the catalytic bed, the platinum paste was mixed with a sacrificial paste that disappeared during sintering, to leave behind a porous and rough layer. As an early development level in manufacturing robust and high-temperature tolerant microthrusters, the influence of design on the temperature gradients and dry temperature tolerance of the devices was studied. On average, the small reaction chambers showed a more than 1.5 times higher dry temperature tolerance (in centigrade) compared to devices with larger chambers, independent of the heater and device size. However, for a given temperature, big devices consumed on average 2.9 times more power than the small ones. It was also found that over the same area and under the same heating conditions, devices with small chambers were subjected to approximately 40% smaller temperature differences. A pressure test done on two small devices with small chambers revealed that pressures of at least 26.3 bar could be tolerated. Above this pressure, the interfaces failed but the devices were not damaged. To investigate the cooling effect of the micropropellant, the endurance of a full thruster was also studied under wet testing where it was fed with 31 wt.% hydrogen peroxide. The thruster demonstrated complete evaporation and/or full decomposition at a power above 3.7 W for a propellant flow of 50 mu l min(-1). At this power, the catalytic bed locally reached a temperature of 147 degrees C. The component was successfully heated to an operating temperature of 307 degrees C, where it cracked. Under these firing conditions, and assuming complete decomposition, calculations give a thrust and specific impulse of 0.96 mN and 106 s, respectively. In the case of evaporation, the corresponding values are calculated to be 0.84 mN and 92 s.

  • 8.
    Khaji, Zahra
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Palmer, Kristoffer
    SSC Nanospace, Uppsala, Sweden.
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Catalytic Effect of Platinum and Silver in a Hydrogen Peroxide Monopropellant Ceramic MicrothrusterIn: Sensors and Actuators A-Physical, ISSN 0924-4247, E-ISSN 1873-3069, ISSN 0924-4247Article in journal (Refereed)
  • 9.
    Khaji, Zahra
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Manufacturing and characterization of a ceramic single-use microvalve2016In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 26, no 9, article id 095002Article in journal (Refereed)
    Abstract [en]

    We present the manufacturing and characterization of a ceramic single-use microvalve withthe potential to be integrated in lab-on-a-chip devices, and forsee its utilization in space andother demanding applications. A 3 mm diameter membrane was used as the flow barrier, andthe opening mechanism was based on cracking the membrane by inducing thermal stresses onit with fast and localized resistive heating.

    Four manufacturing schemes based on high-temperature co-fired ceramic technology werestudied. Three designs for the integrated heaters and two thicknesses of 40 and 120 μmfor the membranes were considered, and the heat distribution over their membranes, therequired heating energies, their opening mode, and the flows admitted through were compared.Furthermore, the effect of applying +1 and −1 bar pressure difference on the membraneduring cracking was investigated. Thick membranes demonstrated unpromising results forlow-pressure applications since the heating either resulted in microcracks or cracking of thewhole chip. Because of the higher pressure tolerance of the thick membranes, the designwith microcracks can be considered for high-pressure applications where flow is facilitatedanyway. Thin membranes, on the other hand, showed different opening sizes depending onheater design and, consequently, heat distribution over the membranes, from microcracks toholes with sizes of 3–100% of the membrane area. For all the designs, applying +1 bar overpressure contributed to bigger openings, whereas −1 bar pressure difference only did so forone of the designs, resulting in smaller openings for the other two. The energy required forbreaking these membranes was a few hundred mJ with no significant dependence on designand applied pressure. The maximum sustainable pressure of the valve for the current designand thin membranes was 7 bar.

  • 10.
    Khaji, Zahra
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Sturesson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC). Swedish National Defence College.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Investigation of the storage and release of oxygen in a Cu-Pt element of a high-temperature microcombustor2014In: The 14th International Conference on Micro and Nanotechnology for Power Generation and Energy Conversion Applications(PowerMEMS 2014), Institute of Physics (IOP), 2014Conference paper (Refereed)
    Abstract [en]

    A miniature combustor for converting organic samples into CO2 with application in carbon isotopic measurements has been manufactured and evaluated. The combustor was made of High-Temperature Co-fired Ceramic (HTCC) alumina green tapes. The device has a built-in screen printed heater and a temperature sensor made of platinum, co-sintered with the ceramic. A copper oxide oxygen supply was added to the combustor after sintering by in-situ electroplating of copper on the heater pattern followed by thermal oxidation. Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and Thermal Gravimetric Analysis (TGA) were used to study electroplating, oxidation and the oxide reduction processes. The temperature sensor was calibrated by use of a thermocouple. It demonstrates a temperature coefficient resistance of 4.66×10−3/°C between 32 and 660 °C. The heat characterization was done up to 1000 °C by using IR thermography, and the results were compared with the data from the temperature sensor. Combustion of starch confirmed the feasibility of using copper oxide as the source of oxygen of combustion.

  • 11.
    Kratz, Henrik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Karlsson, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Eriksson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Köhler, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Stenmark, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Design and Modeling of a thermally regulated communications module for nanospacecraft2006In: Journal of Spacecraft and Rockets, ISSN 0022-4650, E-ISSN 1533-6794, Vol. 43, no 6, p. 1377-1386Article in journal (Refereed)
    Abstract [en]

    A silicon-based integrated communications and thermal management microsystem qualifying for use on Nanospace-1, a modularized microsystem-based advanced integrated nanospacecraft, is presented. The transmitter and receiver share the same module framework with essential differences only in the electronics implementation. A data rate of 1 Mbps for the transmitter and 114 kbps for the receiver is accomplished with a transmitter power for the spacecraft and ground station of 2 and 10 W, respectively. Concurrent triple usage of paraffin as low loss antenna substrate, actuator material, and heat sink is designed and analyzed for the first time. On low-power or short-time high-power dissipation of heat from the electronics, energy is stored as latent heat in this phase-change material acting as a heat sink. Thermal transport through the module is initiated,by actuation of thermal switches when 75% of the paraffin's latent heat is consumed. A static thermal analysis reveals a thermal modulation factor of 5.6 between the on and off states of the thermal switches. The size of the module is 6.6 x 68 x 68 mm, and its weight is 43 g.

  • 12.
    Kratz, Henrik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Öjefors, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Signals and Systems Group.
    Stenmark, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Micromachined S-band Patch Antenna with Reduced Dielectric Constant2006In: Sensors and Actuators A-Physical, ISSN 0924-4247, E-ISSN 1873-3069, Vol. 130-131, p. 478-484Article in journal (Refereed)
    Abstract [en]

    A generic dielectric constant reduction method for silicon substrates is presented in detail along with a process description to produce variable dielectric layers for planar antennas. Virtually any dielectric constant below the value for solid silicon 11.9 can be produced down to the limit of structural durability. A first-order volumetric average yields a dielectric constant of 3.8 for the following bonded micromachined silicon substrates; small honeycomb cells with wall thickness of 16 μm and inner wall length of 87 μm are etched using deep reactive ion etch (DRIE) to 475 μm depth in each of two 525 μm 4 in. high ohmic wafers. These two wafers are bonded together with the etched side of both wafers facing each other. A manufactured coaxial-fed disk-patch S-band antenna illustrates the method to reduce the dielectric constant for a circular zone with a diameter of 50 mm. The antenna is designed for a center frequency of 2.5 GHz based on a lossless substrate with a dielectric constant of 3.8. Adjusting the simulation model to fit the measured values of the antenna indicates a dielectric constant of 2.2, a dielectric loss tangent of 0.002, a bulk conductivity loss of 0.006 S/m, and a resonance frequency of 3.2 GHz. A low frequency analysis in the interval 200–500 MHz with a lumped element model and a low frequency formula for the capacitance between the patch and ground plane indicates a dielectric constant in the order of 2.7–2.8. Based on measurements in an SEM, a corrected average dielectric constant is found to be 2.9. This correction is due to thinner walls than expected in the manufactured honeycomb structure. Antenna lobe characteristics have been measured with a half-power beamwidth of ∼76° in both the E-plane and H-plane at 3.2 GHz.

  • 13.
    Köhler, Johan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Bejhed, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Kratz, Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Bruhn, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Lindberg, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Stenmark, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    A Hybrid Cold Gas Microthruster System for Spacecraft2002In: Sensors and Actuators A-Physical, ISSN 0924-4247, E-ISSN 1873-3069, Vol. 97-98, p. 587-98Article in journal (Refereed)
    Abstract [en]

    A hybrid cold gas microthruster system suitable for low Δv applications on spacecraft have been developed. Microelectromechanical system (MEMS) components together with fine-mechanics form the microthruster units, intergrating four independent thrusters. These are designed to deliver maximum thrusts in the range of 0.1–10 mN.

    The system includes three different micromachined subsystems: a nozzle unit comprising four nozzles generating supersonic gas velocity, i.e. 455 m/s, four independent piezoelectric proportional valves with leak rates at 10−6 scc/s He, and two particle filters. The performances of all these MEMS subsystems have been evaluated.

    The total system performance has been estimated in two parameters, the system-specific impulse and the mass ratio of the propulsion system to the spacecraft mass. These figures provide input for spacecraft design and manufacture.

  • 14.
    Lekholm, Ville
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Persson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Hafnium oxide in high-temperature microelectromechanical systemsManuscript (preprint) (Other academic)
  • 15.
    Palmer, Kristoffer
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Development of Microcomponents for Attitude and Communication Systems on Small Vehicles in Space and Extreme Environments2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In this thesis, components intended for vehicles in space and other extreme environments have been realized using microsystems technology to facilitate miniaturized, yet high-performing systems beneficial for small spacecraft and other vehicles with limited size and power.

    Cold gas thrusters commonly used on spacecraft basically accelerate a gaseous propellant stored under high pressure. When miniaturized, their performance is reduced because of viscous forces. Here, with a special masking and etching scheme, making silicon micronozzles close to rotationally symmetric, this shortcoming was mitigated as indicated by schlieren imaging of the rocket exhaust and a comparison with conventionally manufactured micronozzles with rectangular cross-sections. Schlieren imaging was also used to detect leakage, quantify thrust vector deviation, and measure shock cell periods in the exhaust. Correlation was made to operational conditions.

    Similarly operating zirconia thrusters with integrated heaters and flow sensors were developed to allow for higher operating temperature. Successful testing at 1000°C, suggests that the propellant efficiency could be increased by 7.5%, and also makes them candidates for chemical propulsion.

    A silicon thruster operating in rarefied gas regimes was also developed. Being suspended in a silicon dioxide frame reducing heat losses, a total efficiency of 17% was reached.

    Relating to the integrated micropropulsion systems, two types of flow sensors were developed. Through finite element modeling, the insertion of sensor fingers in the fluid was shown to be an interesting concept for high-pressure applications.

    Utilizing the same principle, a velocity sensor for a miniaturized submersible was developed. With a power consumption below 15 mW, it was able to measure directions with an accuracy of ±8º, and speed with an error less than 22%.

    To enable high-speed optical communication between spacecraft, a Free Space Optics communication system, and particularly its dual-axis beam-steering actuator, was developed. Through thermal actuation, optical angles larger than 40º were obtained. A lumped thermal model was used to study design changes, vacuum operation and feedback control.

    Understanding and mastering heat transfer in microsystems have been vital in many of the studies conducted. Throughout, advanced micromachining and modeling have been used as a step towards high-performance systems for space and other extreme environments.

    List of papers
    1. Schlieren Imaging of Microthruster Exhausts for Qualitative and Quantitative Analysis
    Open this publication in new window or tab >>Schlieren Imaging of Microthruster Exhausts for Qualitative and Quantitative Analysis
    2012 (English)In: Measurement science and technology, ISSN 0957-0233, E-ISSN 1361-6501, Vol. 23, no 8, p. 085403-Article in journal (Refereed) Published
    Abstract [en]

    Abstract. Schlieren imaging is a method used to visualize differences in refractiveindex within a medium. It is a powerful and straightforward tool for sensitiveand high-resolution visualization of, e.g., gas flows. Here, heated cold gasmicrothrusters were studied with this technique. The thrusters are manufacturedusing microelectromechanical systems technology, and measure 22×22×0.85 mm. Thenozzles are approximately 20 µm wide at the throat, and 350 µm wide at the exit.Through these studies, verification of the functionality of the thrusters, and directvisualization and of the thruster exhausts was possible. At atmospheric pressure,slipping of the exhaust was observed, due to severe overexpansion of the nozzle. Invacuum (3 kPa), the exhaust was imaged while feed pressure was varied from 100 to450 kPa. The nozzle was overexpanded, and the flow was seen to be supersonic. Theshock cell period was linearly dependent on feed pressure, ranging from 320 to 610 µm.With activated heaters, the shock cell separation increased. The effect of the heaterswas more prominent at low feed pressure, and an increase in specific impulse of 20%was calculated. It was also shown that schlieren imaging can be used to detect leaks,making it a valuable, safe, and noninvasive aid in quality control of the thrusters.

    Place, publisher, year, edition, pages
    Institute of Physics (IOP), 2012
    Keywords
    Schlieren imaging, microthrusters, MEMS, shock cells
    National Category
    Other Engineering and Technologies not elsewhere specified
    Research subject
    Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-186252 (URN)10.1088/0957-0233/23/8/085403 (DOI)000306366600039 ()
    Funder
    VINNOVA
    Available from: 2012-11-29 Created: 2012-11-28 Last updated: 2017-12-07Bibliographically approved
    2. Investigation of exhausts from fabricated silicon micronozzles with rectangular and close to rotationally symmetric cross sections
    Open this publication in new window or tab >>Investigation of exhausts from fabricated silicon micronozzles with rectangular and close to rotationally symmetric cross sections
    2013 (English)In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 23, no 10, p. 105001-Article in journal (Refereed) Published
    Abstract [en]

    Close to rotationally symmetric in-plane silicon micronozzles with throat and exit diameters of 45 and 260 µm, respectively, have been fabricated using semi-isotropic SF6 etching through an array mask utilizing microloading and reactive ion etching lag. Comparison with nozzles fabricated using deep reactive ion etching (DRIE) and having a rectangular cross-section but a similar hydraulic diameter in the throat, showed that the Reynolds numbers were almost equal even though the DRIE-etched nozzle had an almost five times larger cross-sectional area, hence implying less viscous losses and higher efficiency with the nearly symmetrical nozzles. The nozzle shapes have been studied using x-ray computed tomography. Comparison of the nozzles' exhaust jets using schlieren imaging, showed that the rectangular nozzles' jets deviate from the nozzle axis direction. It is believed that it is caused by the inclined side walls resulting from the DRIE etching. The results from intentionally misaligning the wafers, each containing half a nozzle, 50 µm parallel with or perpendicular to the nozzle axis, showed that the exhaust deviated and widened, respectively. The findings show that the nozzle symmetry affects both the shape and the pointing direction of the exhaust and that schlieren imaging is a powerful tool for determining nozzle thrust vector deviations.

    National Category
    Engineering and Technology
    Research subject
    Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-186774 (URN)10.1088/0960-1317/23/10/105001 (DOI)000324672700002 ()
    Available from: 2012-11-29 Created: 2012-11-29 Last updated: 2017-12-07Bibliographically approved
    3. High-temperature zirconia microthruster with integrated flow sensor
    Open this publication in new window or tab >>High-temperature zirconia microthruster with integrated flow sensor
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    2013 (English)In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 23, no 5, p. 055004-Article in journal (Refereed) Published
    Abstract [en]

    This paper describes the design, fabrication and characterization of a ceramic, heated cold-gas microthruster device made with silicon tools and high temperature co-fired ceramic processing. The device contains two opposing thrusters, each with an integrated calorimetric propellant flow sensor and a heater in the stagnation chamber of the nozzle. The exhaust from a thruster was photographed using schlieren imaging to study its behavior and search for leaks. The heater elements were tested under a cyclic thermal load and to the maximum power before failure. The nozzle heater was shown to improve the efficiency of the thruster by 6.9%, from a specific impulse of 66 to 71 s, as calculated from a decrease of the flow rate through the nozzle of 13%, from 44.9 to 39.2 sccm. The sensitivity of the integrated flow sensor was measured to 0.15 m Omega sccm(-1) in the region of 0-15 sccm and to 0.04 m Omega sccm(-1) above 20 sccm, with a zero-flow sensitivity of 0.27 m Omega sccm(-1). The choice of yttria-stabilized zirconia as a material for the devices makes them robust and capable of surviving temperatures locally exceeding 1000 degrees C.

    Keywords
    Keywords: Zirconia, YSZ, HTCC, schlieren imaging, flow sensor, microthruster
    National Category
    Other Engineering and Technologies not elsewhere specified
    Research subject
    Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-186257 (URN)10.1088/0960-1317/23/5/055004 (DOI)000317739100004 ()
    Funder
    Vinnova
    Available from: 2012-11-28 Created: 2012-11-28 Last updated: 2017-12-07Bibliographically approved
    4. Fabrication and evaluation of a free molecule micro-resistojet with thick silicon dioxide insulation and suspension
    Open this publication in new window or tab >>Fabrication and evaluation of a free molecule micro-resistojet with thick silicon dioxide insulation and suspension
    2013 (English)In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 23, no 6, p. 065006-Article in journal (Refereed) Published
    Abstract [en]

    A silicon free molecule micro-resistojet (FMMR) with a thermally insulating suspension frame composed of silicon dioxide has been designed, fabricated and tested. The concept was developed to increase the efficiency of FMMRs, especially in silicon-based integrated systems. Fabrication of the thick insulating frame was performed through oxidation of high-aspect ratio silicon trenches. The thermal properties of the 1 cm(2) thruster were evaluated using an IR camera, and it was found that when the volume inside the frame is heated more than 200 degrees C using integrated nickel heaters, the temperature increase in the volume outside the frame is less than 50 degrees C. During operation in vacuum, the thrust range was calculated to be about 13-1070 mu N and the maximum specific impulse 54 s. At maximum thrust, and a power consumption of 1.6 W, the total efficiency of the thruster was 17%. Designs of more efficient and versatile systems are discussed.

    National Category
    Engineering and Technology
    Research subject
    Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-186775 (URN)10.1088/0960-1317/23/6/065006 (DOI)000319451300006 ()
    Available from: 2012-11-29 Created: 2012-11-29 Last updated: 2017-12-07Bibliographically approved
    5. A highly integratable silicon thermal gas flow sensor
    Open this publication in new window or tab >>A highly integratable silicon thermal gas flow sensor
    2012 (English)In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 22, no 6, p. 065015-Article in journal (Refereed) Published
    Abstract [en]

    Thermal flow sensors have been designed, fabricated, and characterized. All bulk material in these devices is silicon so that they are integratable in silicon-based microsystems. To mitigate heat losses and to allow for use of corrosive gases, the heating and sensing thin film titanium/platinum elements, injecting and extracting heat, respectively, from the flow, are placed outside the channel on top of a membrane consisting of alternating layers of stress-balancing silicon dioxide and silicon nitride. For the fabrication, an unconventional bond surface protection method using sputter-deposited aluminum instead of thermal silicon dioxide is used in the process steps prior to silicon fusion bonding. A method for performing lift-off on top of the transparent membrane was also developed. The sensors, measuring 9.5 x 9.5 mm(2), are characterized in calorimetric and time-of-flight modes with nitrogen flow rates between 0 sccm and 300 sccm. The maximum calorimetric sensor flow signal and sensitivity are 0.95 mV and 29 mu V sccm(-1), respectively, with power consumption less than 40 mW. The time-of-flight mode is found to have a wider detectable flow range compared with calorimetric mode, and the time of flight measured indicates a response time of the sensor in the millisecond range. The design and operation of a sensor with high sensitivity and large flow range are discussed. A key element of this discussion is the configuration of the array of heaters and gauges along the channel to obtain different sensitivities and extend the operational range. This means that the sensor can be tailored to different flow ranges.

    National Category
    Engineering and Technology
    Research subject
    Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-176814 (URN)10.1088/0960-1317/22/6/065015 (DOI)000304609600015 ()
    Available from: 2012-06-27 Created: 2012-06-26 Last updated: 2017-12-07Bibliographically approved
    6. Finite Element Analysis of the Effect on Employing Thermal Through Vias and Heat Fingers to Increase Heat Transfer to Fluid in Calorimetric Flow Sensors
    Open this publication in new window or tab >>Finite Element Analysis of the Effect on Employing Thermal Through Vias and Heat Fingers to Increase Heat Transfer to Fluid in Calorimetric Flow Sensors
    2013 (English)In: Sensors and Actuators A-Physical, ISSN 0924-4247, E-ISSN 1873-3069, Vol. 201, p. 49-57Article in journal (Refereed) Published
    Abstract [en]

    Measurement results of a robust silicon calorimetric flow sensor with a 25 μm thick silicon dioxide membrane with thermal silicon vias have been compared with results obtained from three-dimensional Finite Element Analysis (FEA). Based on the fabricated device, the sensor has been further developed to include heat-exchanging fingers extending down into the integrated flow channel for increased heat transfer. Using FEA, different designs of the fingers have been compared with respect to signal strength, sensitivity, power consumption and pressure loss in the channel at flow rates from 0 to about 650 sccm. Using heat fingers, the sensor signal was improved by a factor of five. The sensor signal, i.e. the temperature difference between downstream and upstream elements, was more than 60 °C when the central heater was heated 300 °C above room temperature, which was comparable to a thin-membrane device modeled. The maximum sensitivity using the finger design was about 1.4 °C sccm−1, and the maximum power consumption was almost 700 mW, which is considerably higher than for thin-membrane sensors. A figure of merit used for evaluation, was the ratio of signal strength to power consumption. The results show that the device design is a promising concept that is suitable in systems requiring robust monolithically integratable flow sensors.

    National Category
    Engineering and Technology
    Research subject
    Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-186776 (URN)10.1016/j.sna.2013.05.018 (DOI)000325836400006 ()
    Available from: 2012-11-29 Created: 2012-11-29 Last updated: 2017-12-07Bibliographically approved
    7. Two-Dimensional Thermal Velocity Sensor for Submersible navigation and Minute Flow Measurements
    Open this publication in new window or tab >>Two-Dimensional Thermal Velocity Sensor for Submersible navigation and Minute Flow Measurements
    2013 (English)In: IEEE Sensors Journal, ISSN 1530-437X, E-ISSN 1558-1748, Vol. 13, no 1, p. 359-370Article in journal (Refereed) Published
    Abstract [en]

    A 2-D thermal velocity microsensor for use as a navigational aid and for flow measurements on a miniaturized submersible is developed in this paper. The sensor with nickel heater and temperature sensors on a Pyrex substrate, designed for mounting on the outside of the submersible hull, is fabricated and tested in an application-like environment and proven to be able to measure water speed from zero to 40 mm/s with a power consumption less than 15 mW and determine the flow direction with an error less than ±8°. Finite Element Analysis is used to investigate design and operation parameters and possible biofouling effects on the sensor signal. The effect on shape and orientation of the sensor's mounting surface is also studied.

    National Category
    Other Materials Engineering
    Research subject
    Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-171767 (URN)10.1109/JSEN.2012.2216866 (DOI)000313685400028 ()
    Available from: 2012-03-27 Created: 2012-03-27 Last updated: 2017-12-07Bibliographically approved
    8. A micromachined dual-axis beam steering actuator for use in a miniaturized optical space communication system
    Open this publication in new window or tab >>A micromachined dual-axis beam steering actuator for use in a miniaturized optical space communication system
    Show others...
    2010 (English)In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 20, no 10, p. 105007-Article in journal (Refereed) Published
    Abstract [en]

    The design, fabrication and evaluation of an electrothermally actuated micromachined beam steering device for use in a free-space optical communication system intended for use on micro-and nanospacecraft in kilometer-sized formations are presented. SU-8 confined in v-grooves is heated to create bending movement in two orthogonal directions for two-axial steering with large static bending angles and low actuation voltages. Standard MEMS processing is used to fabricate the devices with square mirror side lengths of 1, 3.5 and 5 mm. In addition, a method to prevent thermal damage to SU-8 during deep reactive ion etching has been successfully developed. Characterization shows optical scan ranges larger than 40 degrees in both directions with the maximum driving voltage of 16 V corresponding to a total power consumption of 1.14 W. Infrared imaging is used to investigate thermal cross-talk between actuators for the two scanning directions. It is found that a silicon backbone on the joint backside is crucial for device performance. Differences from expected performance are believed to arise from the SU-8 curing process and excessive heating during fabrication. A finite element method simulation is used to find the eigenfrequencies of the structures, and these are in good agreement with the measured frequency response.

    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:uu:diva-134362 (URN)10.1088/0960-1317/20/10/105007 (DOI)000282270300020 ()
    Available from: 2010-11-25 Created: 2010-11-24 Last updated: 2017-12-12
    9. Dynamic characterization and modelling of a dual-axis beam steering device for performance understanding, optimization, and control design
    Open this publication in new window or tab >>Dynamic characterization and modelling of a dual-axis beam steering device for performance understanding, optimization, and control design
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    2013 (English)In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 23, no 4, p. 045020-Article in journal (Refereed) Published
    Abstract [en]

    This paper presents a lumped thermal model of a dual-axis laser micromirror device for beam steering in a free-space optical (FSO) communication system, designed for fractionated spacecraft. An FSO communication system provides several advantages, such as larger bandwidth, smaller size and weight of the communication payload and less power consumption. A dual-axis mirror device is designed and realized using microelectromechanical systems technology. The fabrication is based on a double-sided, bulk micromachining process, where the mirror actuates thermally by joints consisting of v-grooves filled with the SU-8 polymer. The size of the device, consisting of a mirror, which is deflectable versus its frame in one direction, and through deflection of the frame in the other, is 15.4 × 10.4 × 0.3 mm3. In order to further characterize and understand the micromirror device, a Simulink state-space model of the actuator is set up using thermal and mechanical properties from a realized actuator. A deviation of less than 2% between the modelled and measured devices was obtained in an actuating temperature range of 20–200 °C. The model of the physical device was examined by evaluating its performance in vacuum, and by changing physical parameters, such as thickness and material composition. By this, design parameters were evaluated for performance gain and usability. For example, the crosstalk between the two actuators deflecting the mirror along its two axes in atmospheric pressure is projected to go down from 97% to 6% when changing the frame material from silicon to silicon dioxide. A feedback control system was also designed around the model in order to examine the possibility to make a robust control system for the physical device. In conclusion, the model of the actuator presented in this paper can be used for further understanding and development of the actuator system.

    National Category
    Communication Systems
    Research subject
    Engineering Science with specialization in Microsystems Technology; Engineering Science with specialization in Electronics
    Identifiers
    urn:nbn:se:uu:diva-185627 (URN)10.1088/0960-1317/23/4/045020 (DOI)000316299900021 ()
    Available from: 2012-11-27 Created: 2012-11-27 Last updated: 2017-12-07Bibliographically approved
  • 16.
    Persson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Magnetoresistance and Space: Micro- and Nanofeature Sensors Designed, Manufactured and Evaluated for Space Magnetic Field Investigations 2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In recent years, the interest for miniaturization of spaceborne instruments and subsystems has increased steadily, as this enables development of small and lightweight satellite classes as well as more versatile payloads on traditional spacecraft.

    In essence, this thesis work is an investigation of the applicability of magnetoresistive technology to a magnetometer intended for space. Two types of magnetoresistive sensors, promising with respect to performance competiveness also after considerable miniaturization, were developed and evaluated, namely magnetic tunnel junctions and planar Hall effect bridge sensors.

    In the case of the magnetic tunnel junctions, much effort was put on the micromanufacturing process. Two schemes were developed and evaluated for sensor contouring: one employing focused ion beam processes for rapid prototyping, and the other combining sputtering and x-ray photoelectron spectroscopy for precise etch depth monitoring during ion etching. For the former, the resulting implantation damages were investigated with chemical analysis and correlated to the sensor properties. In the latter, the depth of the etching was monitored live with a resolution sufficient to stop the etching in the 1 nm thick tunneling barrier. The effect and extent of redeposition were investigated by transmission electron microscopy and micromagnetic analysis. With the knowledge so gained, the tunneling magnetoresistance of the manufactured junctions could be improved significantly and their inherent noise could be reduced. As a step in space flight qualification, the magnetic tunnel junctions were subjected to both g and particle radiation, leaving them unaffected by the first, but rendering them a reduced tunneling magnetoresistance ratio and an increased coercivity by the latter.

    In the case of the planar Hall effect bridge sensors, their inherent noise was thoroughly investigated, revealing both electric and magnetic 1/f noise at low frequencies along with thermal noise at higher frequencies. In addition, an analytical model of the magnetic properties of the planar Hall effect bridges was developed, and a design process, based on the model, was established to optimize the bridges for a particular application.

    In conclusion, both types of sensors show great promises for use in space. Of the two, the planar Hall effect bridge sensors had a better detection limit at low frequencies, whereas the magnetic tunnel junctions were more precise at higher frequencies. However, both sensors had a bandwidth greatly exceeding that of traditional spaceborne magnetometers. A magnetometer employing the magnetic tunnel junctions from this work is currently included as payload onboard the Vietnamese satellite F-1 scheduled for launch this year. A magnetometer using magnetoresistive sensors – planar Hall effect sensors, magnetic tunnel junctions, or both – enables a mass reduction of more than two orders of magnitudes compared with traditional systems.

    List of papers
    1. Low-frequency noise in planar Hall effect bridge sensors
    Open this publication in new window or tab >>Low-frequency noise in planar Hall effect bridge sensors
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    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    The low-frequency characteristics of planar Hall effect bridge sensors are investigated as function of the sensor bias current and the applied magnetic field. The noise spectra reveal a Johnson-like spectrum at high frequencies, and a 1/f-like excess noise spectrum at lower frequencies, with a knee frequency of around 400 Hz. The 1/f-like excess noise can be described by the phenomenological Hooge equation with a Hooge parameter of gH=0.016. The detectivity is shown to depend on the total length, width and thickness of the bridge branches. Increasing the total length by a factor of 10 improves the detectivity by a factor of 101/2. Moreover, the detectivity is shown to depend on the amplitude of the applied magnetic field, revealing a magnetic origin to part of the 1/f noise.

    Keywords
    Magnetoresistance, Planar Hall effect, Low-frequency noise, Detectivity
    National Category
    Materials Engineering
    Research subject
    Engineering Science with specialization in Solid State Physics; Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-153314 (URN)
    Funder
    Knut and Alice Wallenberg FoundationSwedish Research Council
    Available from: 2011-05-10 Created: 2011-05-10 Last updated: 2011-07-01Bibliographically approved
    2. Low-frequency picotesla field detection with planar Hall effect bridge sensors
    Open this publication in new window or tab >>Low-frequency picotesla field detection with planar Hall effect bridge sensors
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    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    The applicability of miniaturized magnetic field sensors are being explored in several fields of magnetic field detection, due to their integratability, low mass, and potentially low cost. In this respect, different thin-film technologies, especially those employing magnetoresistance, show great potential, being compatible with micro- and nanotechnology batch processing. For low-frequency magnetic field detection, sensors based on the planar Hall effect, especially planar Hall effect bridge (PHEB) sensors, show promising performance given their inherent low-field linearity, limited hysteresis and moderate noise figure. In this work, the applicability of such PHEB sensors to different areas is investigated. An analytical model was constructed, to estimate the performance of an arbitrary PHEB in terms of e.g. sensitivity and detectivity. The model incorporates a number of approximations and, to validate the results, modelled data is compared to measurements on actual PHEBs. It is concluded that the model slightly underestimated the detectivity, especially at low frequencies and when demagnetizing effects becomes apparent. The model is also sensitive to fabrication process induced variations of the material parameters of the sensors. Nevertheless, accounting for these discrepancies, the modelled data is typically within 10% from the experimental data and the model can be used to estimate the performance of a particular PHEB design. The model is also used to establish a design process for optimizing a PHEB to a particular set of requirements on the bandwidth, detectivity, compliance voltage and amplified signal-to-noise ratio. By applying this design process, the size, sensitivity, resistance, bias current and power consumption of the PHEB can be calculated. The model shows that PHEBs are applicable to several different science areas including archaeological surveying, satellite attitude determination, scientific space missions, and magnetic bead detection in lab-on-a-chip applications.

    National Category
    Materials Engineering
    Research subject
    Engineering Science with specialization in Solid State Physics; Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-153315 (URN)
    Funder
    Knut and Alice Wallenberg FoundationSwedish Research Council
    Available from: 2011-05-10 Created: 2011-05-10 Last updated: 2011-07-01Bibliographically approved
    3. Rapid prototyping of magnetic tunnel junctions with focused ion beam processes
    Open this publication in new window or tab >>Rapid prototyping of magnetic tunnel junctions with focused ion beam processes
    2010 (English)In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 20, no 5, p. 055039-Article in journal (Refereed) Published
    Abstract [en]

    Submicron sized Magnetic tunnel junctions (MTJs) are most often fabricated by time-consuming and expensive e-beam lithography. From a research and development perspective, a short lead time is one of the major concerns. Here, a rapid process scheme for fabrication of micrometer size MTJs with focused ion beam processes is presented. The magnetic properties of the fabricated junctions is investigated in terms of magnetic domain structure, tunnelling magnetoresistance (TMR) and coercivity, with extra attention to the effect of Ga implantation from the ion beam. In particular, the effect of the implantation on the minimum junction size and the magnetization of the sensing layer are studied. In the latter case, magnetic force microscopy and micromagnetic simulations, with the Object Oriented Micromagnetic Framework (OOMMF), are used to study the magnetization reversal. The fabricated junctions show considerable coercivity both along their hard and easy axes. Interestingly, the sensing layer exhibit two remanent states: one with a single and one with a double domain. The hard axis TMR loop has kinks at about ±20 mT which is attributed to a non-uniform lateral coercivity, where the rim of the junctions, which is subjected to Ga implantation from the flank of the ion beam, is more coercive than the unirradiated centre. The width of the coercive rim is estimated to 160 nm from the hard axis TMR loop. The easy axis TMR loop shows more coercivity than an unirradiated junction and, this too, is found to stem from the coercive rim, as seen from the simulations. It is concluded that the process scheme has three major advantages. Firstly, it has a high lateral and depth resolution – the depth resolution is enhanced by end point detection – and is capable of making junctions of sizes down towards the limit set by the width of the irradiated rim. Secondly, the most delicate process steps are preformed in unbroken vacuum enabling the use of materials prone to forming oxides in the MTJ film stack. Thirdly, the scheme is both uncomplicated and quick and makes it possible to go from design to characterization in the order of hours.

    Place, publisher, year, edition, pages
    IOP, 2010
    National Category
    Materials Engineering
    Research subject
    Materials Science
    Identifiers
    urn:nbn:se:uu:diva-134753 (URN)10.1088/0960-1317/20/5/055039 (DOI)000277305000039 ()
    Available from: 2010-12-01 Created: 2010-11-30 Last updated: 2017-12-12Bibliographically approved
    4. Ga Implantation in a MgO-based Magnetic Tunnel Junction With Co60Fe20B20 Layers
    Open this publication in new window or tab >>Ga Implantation in a MgO-based Magnetic Tunnel Junction With Co60Fe20B20 Layers
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    2011 (English)In: IEEE transactions on magnetics, ISSN 0018-9464, E-ISSN 1941-0069, Vol. 47, no 1, p. 151-155Article in journal (Refereed) Published
    Abstract [en]

    A Co60Fe20B20-based tunneling magnetoresistance multilayer stack with an MgO barrier has been exposed to 30 keV Ga ions at doses corresponding to ion etching and metal deposition in a focused ion beam (FIB) instrument, to study the applicability of these processes to magnetic tunnel junction (MTJ) fabrication. MTJs were fabricated and irradiated to investigate how the exposures affected their coercivity and magnetoresistance. Elemental depth profiles, acquired using electron spectroscopy for chemical analysis, showed that Ga gathered in and around the two Co60Fe20B20 layers. Correlated with the results of the magnetic measurements, this Ga presence was found to cause a reduction of magnetoresistance and an increase in coercivity. Quantitatively, a dose of 1014 Ga+cm-2 reduced the magnetoresistance by 60%, whereas a dose of 1015 Ga+cm-2 reduced the magnetoresistance by 67% and also increased the coercivity by 2 mT and changed the dipole coupling between the sensing and the pinning layers by 1.6 mT. The latter was attributed to an imbalance in the synthetic antiferromagnetic structure, where the stack's Ru spacer served as an implantation barrier. The magnetoresistance was lost at a dose of 1016 Ga+cm-2. Annealing reduced the content of Ga around the magnetic layers but also caused diffusion of Cu from one of the layers in the stack. Apart from the observation and explanation of implantation damages in the multilayer, this work concludes on the applicability of FIB processes for prototyping of MTJs.

    Keywords
    Focused ion beam, gallium implantation, magnetic tunnel junction, tunneling magnetoresistance
    National Category
    Materials Engineering
    Research subject
    Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-142866 (URN)10.1109/TMAG.2010.2089634 (DOI)000285843800001 ()
    Available from: 2011-01-18 Created: 2011-01-17 Last updated: 2017-12-11Bibliographically approved
    5. Material- and fabrication-governed performance of a tunnelling magnetometer
    Open this publication in new window or tab >>Material- and fabrication-governed performance of a tunnelling magnetometer
    2010 (English)Conference paper, Published paper (Refereed)
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:uu:diva-140889 (URN)
    Conference
    The 5th International Workshop on Advanced Materials Science and Nanotechnology, IWAMSN2010, Hanoi, Vietnam, 2010
    Available from: 2011-01-10 Created: 2011-01-10 Last updated: 2015-01-07
    6. Etch-stop technique for patterning of tunnel junctions for a magnetic field sensor
    Open this publication in new window or tab >>Etch-stop technique for patterning of tunnel junctions for a magnetic field sensor
    2011 (English)In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 21, no 4, p. 045014-045022Article in journal (Refereed) Published
    Abstract [en]

    Spin-dependent tunnelling devices, e. g. magnetic random access memories and highly sensitive tunnelling magnetoresistance (TMR) sensors, often consist of a large number of magnetic tunnel junctions (MTJs) of uniform quality over the whole device. The uniformity and yield of the fabrication of such a device are therefore very important. A major source of yield loss is the short-circuiting of junctions by redeposition of etch residues. This can be prevented by terminating of the etch in the typically 1 nm thick tunnelling barrier. Here, electron spectroscopy for chemical analysis for monitoring the etching semi-continuously is proposed. The fabrication scheme employs Ar ion milling for etching the MTJs, and photoelectron spectroscopy for analysing the composition of the etched surface in situ. Junctions etched either to or through the barrier were used for this. The quality of the etch stop was investigated using transmission electron microscopy (TEM), and it was confirmed that the etch could be stopped in the MgO barrier. The TEM imaging also showed clear signs of redeposition. Such redeposition was attributed to being partly caused by the reduction of the TMR ratio of the junctions etched through the barrier, which was only 15% as compared with 150% for junctions etched to the barrier. Also, the latter junctions exhibited 2.7 times less noise in the low-frequency regime, resulting in a 27 times improvement of the signal-to-noise ratio with the etch stop. The barrier also proved effective in protecting the bottom contact from oxidation during the capping and contacting of the junctions.

    National Category
    Engineering and Technology
    Research subject
    Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-151972 (URN)10.1088/0960-1317/21/4/045014 (DOI)000288751400016 ()
    Available from: 2011-04-26 Created: 2011-04-20 Last updated: 2017-12-11Bibliographically approved
    7. Radiation tolerance of a spin-dependent tunnelling magnetometer for space applications
    Open this publication in new window or tab >>Radiation tolerance of a spin-dependent tunnelling magnetometer for space applications
    2011 (English)In: Measurement science and technology, ISSN 0957-0233, E-ISSN 1361-6501, Vol. 22, no 4, p. 045204-Article in journal (Refereed) Published
    Abstract [en]

    To meet the increasing demand for miniaturized space instruments, efforts have been made to miniaturize traditional magnetometers, e. g. fluxgate and spin-exchange relaxation-free magnetometers. These have, for different reasons, turned out to be difficult. New technologies are needed, and promising in this respect are tunnelling magnetoresistive (TMR) magnetometers, which are based on thin film technology. However, all new space devices first have to be qualified, particularly in terms of radiation resistance. A study on TMR magnetometers' vulnerability to radiation is crucial, considering the fact that they employ a dielectric barrier, which can be susceptible to charge trapping from ionizing radiation. Here, a TMR-based magnetometer, called the spin-dependent tunnelling magnetometer (SDTM), is presented. A magnetometer chip consisting of three Wheatstone bridges, with an angular pitch of 120 degrees, was fabricated using microstructure technology. Each branch of the Wheatstone bridges consists of eight pairs of magnetic tunnel junctions (MTJs) connected in series. Two such chips are used to measure the three-dimensional magnetic field vector. To investigate the SDTM's resistance to radiation, one branch of a Wheatstone bridge was irradiated with gamma rays from a Co-60 source with a dose rate of 10.9 rad min(-1) to a total dose of 100 krad. The TMR of the branch was monitored in situ, and the easy axis TMR loop and low-frequency noise characteristics of a single MTJ were acquired before and after irradiation with the total dose. It was concluded that radiation did not influence the MTJs in any noticeable way in terms of the TMR ratio, coercivity, magnetostatic coupling or low-frequency noise.

    Keywords
    radiation tolerant, magnetic tunnel junction, tunnelling magnetoresistance, magnetometer
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:uu:diva-150729 (URN)10.1088/0957-0233/22/4/045204 (DOI)000288454500010 ()
    Available from: 2011-04-05 Created: 2011-04-05 Last updated: 2017-12-11Bibliographically approved
  • 17.
    Persson, Anders
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Bejhed, Rebecca
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Gunnarsson, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Nguyen, Hugo
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Dalslet, Bjarke T.
    Dept. of Micro- and Nanotechnology, Technical University of Denmark.
    Oesterberg, Frederik W.
    Dept. of Micro- and Nanotechnology, Technical University of Denmark.
    Hansen, Mikkel F.
    Svedlindh, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Low-frequency picotesla field detection with planar Hall effect bridge sensorsManuscript (preprint) (Other academic)
    Abstract [en]

    The applicability of miniaturized magnetic field sensors are being explored in several fields of magnetic field detection, due to their integratability, low mass, and potentially low cost. In this respect, different thin-film technologies, especially those employing magnetoresistance, show great potential, being compatible with micro- and nanotechnology batch processing. For low-frequency magnetic field detection, sensors based on the planar Hall effect, especially planar Hall effect bridge (PHEB) sensors, show promising performance given their inherent low-field linearity, limited hysteresis and moderate noise figure. In this work, the applicability of such PHEB sensors to different areas is investigated. An analytical model was constructed, to estimate the performance of an arbitrary PHEB in terms of e.g. sensitivity and detectivity. The model incorporates a number of approximations and, to validate the results, modelled data is compared to measurements on actual PHEBs. It is concluded that the model slightly underestimated the detectivity, especially at low frequencies and when demagnetizing effects becomes apparent. The model is also sensitive to fabrication process induced variations of the material parameters of the sensors. Nevertheless, accounting for these discrepancies, the modelled data is typically within 10% from the experimental data and the model can be used to estimate the performance of a particular PHEB design. The model is also used to establish a design process for optimizing a PHEB to a particular set of requirements on the bandwidth, detectivity, compliance voltage and amplified signal-to-noise ratio. By applying this design process, the size, sensitivity, resistance, bias current and power consumption of the PHEB can be calculated. The model shows that PHEBs are applicable to several different science areas including archaeological surveying, satellite attitude determination, scientific space missions, and magnetic bead detection in lab-on-a-chip applications.

  • 18.
    Persson, Anders
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Bejhed, Rebecca
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Nguyen, Hugo
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Gunnarsson, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Dalslet, Bjarke T.
    Dept. of Micro- and Nanotechnology, Technical University of Denmark.
    Oesterberg, Frederik W.
    Dept. of Micro- and Nanotechnology, Technical University of Denmark.
    Hansen, Mikkel F.
    Svedlindh, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Low-frequency noise in planar Hall effect bridge sensorsManuscript (preprint) (Other academic)
    Abstract [en]

    The low-frequency characteristics of planar Hall effect bridge sensors are investigated as function of the sensor bias current and the applied magnetic field. The noise spectra reveal a Johnson-like spectrum at high frequencies, and a 1/f-like excess noise spectrum at lower frequencies, with a knee frequency of around 400 Hz. The 1/f-like excess noise can be described by the phenomenological Hooge equation with a Hooge parameter of gH=0.016. The detectivity is shown to depend on the total length, width and thickness of the bridge branches. Increasing the total length by a factor of 10 improves the detectivity by a factor of 101/2. Moreover, the detectivity is shown to depend on the amplitude of the applied magnetic field, revealing a magnetic origin to part of the 1/f noise.

  • 19.
    Persson, Anders
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Berglund, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Khaji, Zahra
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Sturesson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC). Swedish Def Univ, Div Mil Technol, Dept Mil Sci, Stockholm, Sweden.
    Söderberg, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Optogalvanic spectroscopy with microplasma sources – Current status and development towards lab on a chip2016In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 26, no 10, article id 104003Article in journal (Refereed)
    Abstract [en]

    Miniaturized optogalvanic spectroscopy (OGS) shows excellent prospects of becoming ahighly sensitive method for gas analysis in micro total analysis systems. Here, a status reporton the current development of microwave induced microplasma sources for OGS is presented,together with the first comparison of the sensitivity of the method to conventional single-passabsorption spectroscopy. The studied microplasma sources are stripline split-ring resonators(SSRRs), with typical ring radii between 3.5 and 6 mm and operation frequencies around2.6 GHz. A linear response (R2 = 0.9999), and a stability of more than 100 s are demonstratedwhen using the microplasma source as an optogalvanic detector. Additionally, saturationeffects at laser powers higher than 100 mW are observed, and the temporal response of theplasma to periodic laser perturbation with repletion rates between 20 Hz and 200 Hz arestudied. Finally, the potential of integrating additional functionality with the detector isdiscussed, with the particular focus on a pressure sensor and a miniaturized combustor toallow for studies of solid samples.

  • 20.
    Smedfors, Katarina
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    A microtechnology-based sensor system for deepwater analysis from a miniaturized submersible2010Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The aim of this master thesis has been to design, and partly manufacture and evaluate, a highly miniaturized, on-chip conductivity-temperature-depth (CTD) sensor system for deepwater analysis also including electrodes for pH and chloride ion concentration measurements. The microtechnology-based sensor system will be a vital instrument onboard the Deeper Access, Deeper Understanding submersible, which will be small enough for deployment through bore holes into the subglacial lakes of Antarctica. Design of the complete 15 x 30 mm chip, including variations of each sensor type (in total 39 sensors), is presented. Salinity (through conductivity), temperature, chloride ion concentration and pH sensors have been manufactured using conventional lithography, evaporation, wet etching and lift off techniques. Simulations of the pressure sensors (not manufactured) show how the set of four bossed membranes with integrated strain gauges combine to cover, yet withstand, pressures of 1-100 atm. Salinity is measured conductively with gold electrodes. The temperature sensor is a platinum thermoresistor. Chloride ion concentration and pH are measured potentiometrically with ion-selective microelectrodes of silver/silver chloride and iridium oxide, respectively. Tests of the conductivity sensor gave good results also on sea water samples of known salinity. The temperature sensor showed good linearity to a reference sensor in the tested range of 5-35 C. Issues with evaporation and lift off are discussed, and a process identification document is attached.

  • 21.
    Snögren, Pär
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC). Uppsala Universitet.
    Highly Integrated Flow Sensor for a Sample Analysis System for Planetary Exploration2016Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In this thesis, an integrated flow sensor for an optogalvanic spectrometer is studied. Optogalvanic spectroscopy can be used for carbon isotope analysis when, e.g., searching life in space. At the heart of the spectrometer is a microplasma source, in which the analysis is performed.

    This master thesis examines the possibilities to integrate a flow sensor inside the microplasma source, to be able to improve the isotopic analysis. The report covers design, manufacturing and evaluation of both the device and the experimental setup. The device was manufactured by milling and lamination of printed circuit board, in which both the plasma source and sensors were incorporated. The final results shows that the sensor had a linear and reliable flow response in a range between 1-15 sccm, and, quite surprisingly, that is simultaneously could measure the pressure in a range between 1-6 Torr. In other words, not only one but two sensors were integrated in the spectrometer at once.

    The work has been done at the Ångström Space Technology Center - a research group within the Department of Engineering Science at Uppsala University.

  • 22.
    Snögren, Pär
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Berglund, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Persson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Combined pressure and flow sensor integrated in a split-ring resonator microplasma source2016In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 109, no 17, article id 173508Article in journal (Refereed)
    Abstract [en]

    Monitoring and control of the principal properties of a discharge or plasma is vital in many applications, and sensors for measuring them must be integrated close to the plasma source in order to deliver reliable results. This is particularly important, and challenging, in miniaturized systems, where different compatibility issues sets the closest level of integration. In this paper, a sensor for simultaneous measurement of the pressure and flow through a stripline split-ring resonator microplasma source is presented. The sensor utilize fully integrated electrodes positioned upstream and downstream of the microplasma source to study these parameters, and was found to deliver uniform and unambiguous results in a pressure and flow range of 1-6 Torr and 1-15 sccm, respectively. Furthermore, hysteresis and drift in the measurements was found to be mitigated by introducing a resistor in parallel with the plasma, in order to facilitate discharging of the electrodes. Combined, the results show that the sensor is fully compatible with miniaturized microfluidic systems in general, and a system for optogalvanic spectroscopy in particular.

  • 23.
    Sturesson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC). Försvarshögskolan/Swedish National Defence College.
    Sense, Actuate and Survive: Ceramic Microsystems for High-Temperature Aerospace Applications2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In aerospace applications, but also in manufacturing, mining, energy industry and natural hazards, high temperature, corrosion, erosion and radiation, challenge the performance and being of hardware.

    In this work, high-temperature co-fired ceramic (HTCC) alumina and platinum have been used for a range of devices intended for aerospace applications at up to 1000°C.

    The thermomechanics of a pressure sensor was investigated, and the interfacing was attained by wireless powering and reading. However, read range was limited and sensitivity decreased with temperature. Silver, electroplated after sintering, was found to remedy this until it eventually alloyed with platinum.

    Copper was electroplated and oxidized for oxygen storage in a microcombustor, intended for sample preparation for optogalvanic spectroscopy (OGS) to indicate extraterrestrial life. Despite delamination, caused by residual stresses, the device operated successfully.

    Conversely, pre-firing metallization by integration of platinum wires was studied. Freely suspended, and despite heat-induced shape irregularities, these were found advantageous over screen printed elements for gas heating, and temperature and pressure sensing. By fusing off the wires, spherical tips, allowing for impedance monitoring of microplasma sources in, e.g., OGS, were formed.

    Microplasma sources can also be used for gas heating. This, together with screen printed and suspended resistive heaters, was evaluated in a microthruster, showing that plasma heating is the most effective, implying fuel consumption reduction in satellite propulsion.

    In conclusion, HTCC alumina microdevices are thermally stable and could benefit several aerospace applications, especially with the complementary metallization schemes devised here.

    Future developments are expected to include both processing and design, all with the intention of sensing, actuating and surviving in high-temperature environments.

    List of papers
    1. Thermomechanical properties and performance of ceramic resonators for wireless pressure reading in high temperatures
    Open this publication in new window or tab >>Thermomechanical properties and performance of ceramic resonators for wireless pressure reading in high temperatures
    Show others...
    2015 (English)In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 25, no 9, article id 095016Article in journal (Refereed) Published
    Abstract [en]

    This paper reports on the design, fabrication and thermomechanical study of ceramic LC resonators for wireless pressure reading, verified at room temperature, at 500 °C and at 1000 °C for pressures up to 2.5 bar. Five different devices were fabricated of high-temperature co-fired ceramics (HTCC) and characterized. Alumina green tape sheets were screen printed with platinum paste, micromachined, laminated and fired. The resulting samples were 21 x 19 mm2 with different thicknesses. An embedded communicator part was integrated with either a passive backing part or with a pressure-sensing element, including an 80 μm thick and 6 mm diameter diaphragm. The study includes measuring thermally and mechanically induced resonance frequency shifts, and thermally induced deformations. For the pressure sensor device, contributions from changes in the relative permittivity and from expanding air, trapped in the cavity, were extracted. The devices exhibited thermomechanical robustness during heating, regardless of the thickness of the backing. The pressure sensitivity decreased with increasing temperature from 15 050 ppm/bar at room temperature to 2400 ppm/bar at 1000°C, due to the decreasing pressure difference between the external pressure and the air pressure inside the cavity. 

    Keywords
    Wireless Reading, HTCC, Pressure sensing, Harsh Environments, Thermomechanical properties
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:uu:diva-253555 (URN)10.1088/0960-1317/25/9/095016 (DOI)000365167700023 ()
    Funder
    Knut and Alice Wallenberg Foundation
    Available from: 2015-05-29 Created: 2015-05-29 Last updated: 2018-08-03Bibliographically approved
    2. Ceramic Pressure Sensor for High Temperatures – Investigation of the Effect of Metallizationon on Read Range
    Open this publication in new window or tab >>Ceramic Pressure Sensor for High Temperatures – Investigation of the Effect of Metallizationon on Read Range
    2017 (English)In: IEEE Sensors Journal, ISSN 1530-437X, E-ISSN 1558-1748, Vol. 17, no 8, p. 2411-2421Article in journal (Refereed) Published
    Abstract [en]

    A study on the relationship between circuit metallization, made by double-layer screen printing of platinum and electroplating of silver on top of platinum, and its impact on practical read range of ceramic LC resonators for high-temperature pressure measurements is presented. Also included is the first realization of membranes by draping a graphite insert with ceramic green body sheets. As a quality factor circuit reference, two-port microstrip meander devices were positively evaluated and to study interdiffusion between silver and platinum, test samples were annealed at 500 degrees C, 700 degrees C, and 900 degrees C for 4, 36, 72, and 96 h. The LC resonators were fabricated with both metallization methods, and the practical read range at room temperature was evaluated. Pressure-sensitive membranes were characterized for pressures up to 2.5 bar at room temperature, 500 degrees C and up to 900 degrees C. Samples electroplated with silver exhibited performance equal to or better than double-layer platinum samples for up to 60 h at 500 degrees C, 20 h at 700 degrees C, and for 1 h at 900 degrees C, which was correlated with the degree of interdiffusion as determined from cross-sectional analysis. The LC resonator samples with double-layer platinum exhibited a read range of 61 mm, and the samples with platinum and silver exhibited a read range of 59 mm. The lowest sheet resistance, and, thereby, the highest read range of 86 mm, was obtained with a silver electroplated LC resonator sample after 36 h of annealing at 500 degrees C.

    Keywords
    Alternative metallization, ceramic membrane, harsh environment sensor, high temperature co-fired ceramics (HTCC), HTCC processing, LC resonator, pressure sensor, wireless reading
    National Category
    Accelerator Physics and Instrumentation Engineering and Technology
    Research subject
    Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-302852 (URN)10.1109/JSEN.2017.2671418 (DOI)000398890800016 ()
    Available from: 2016-09-11 Created: 2016-09-11 Last updated: 2018-08-03Bibliographically approved
    3. Manufacturing and characterization of a ceramic microcombustor with integrated oxygen storage and release element
    Open this publication in new window or tab >>Manufacturing and characterization of a ceramic microcombustor with integrated oxygen storage and release element
    Show others...
    2015 (English)In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 25, no 10, article id 104006Article in journal (Refereed) Published
    Abstract [en]

    A microscale ceramic high-temperature combustor with a built-in temperature sensor and source of oxygen has been designed, manufactured and characterized. The successful in situ electroplating and oxidation of copper, and the use of copper oxide as the source of oxygen were demonstrated. It was shown that residual stresses from electroplating, copper oxidation and oxide decomposition did not cause much deformation of the substrate but influenced mainly the integrity and adhesion of the metal films. The process had influence on the electrical resistances, however. Calibration of the temperature sensor and correlation with IR thermography up to 1000°C revealed a nearly linear sensor behavior. Demonstration of combustion in a vacuum chamber proved that no combustion had occurred before release of oxygen from the metal oxide resource.

    Place, publisher, year, edition, pages
    Institute of Physics (IOP), 2015
    Keywords
    isotopic analysis, HTCC, combustor, EDS, TGA, RGA, oxygen release
    National Category
    Engineering and Technology
    Research subject
    Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-264147 (URN)10.1088/0960-1317/25/10/104006 (DOI)000366827400007 ()
    Funder
    Swedish National Space Board
    Available from: 2015-10-06 Created: 2015-10-06 Last updated: 2018-08-03Bibliographically approved
    4. Pirani Microgauge Fabricated of High-Temperature Co-fired Ceramics with Integrated Platinum Wires
    Open this publication in new window or tab >>Pirani Microgauge Fabricated of High-Temperature Co-fired Ceramics with Integrated Platinum Wires
    2019 (English)In: Sensors and Actuators A-Physical, ISSN 0924-4247, E-ISSN 1873-3069, Vol. 285, p. 8-16Article in journal (Refereed) Published
    Abstract [en]

    This paper presents the integration and pressure sensor operation of platinum bond wires in High-Temperature Co-fired alumina (HTCC). Devices were fabricated with a 50 μm diameter wire suspended across a 500 μm wide cavity in green-body state HTCC, electrically connected to screen printed alumina conductors. The substrate shrinkage during sintering to a cavity width of 400 μm causes the wire element to elevate from the cavity´s bottom surface. Resulting devices were compared with reference devices, containing screen-printed sensor elements, as Pirani gauges operated at 100 °C in constant-resistance mode, and in dynamic mode with a feeding current of 1 A in a pressure range from 10−4 Torr to atmospheric pressure. Also, devices with wire lengths between 500 and 3500 μm were operated and studied in constant-resistance and dynamic mode. Lastly, a device is demonstrated in operation at a mean temperature of 830 °C. The results include wire elements with a consistent elevation from their substrate surfaces, with irregularities along the wires. The wire devices exhibit a faster pressure response in dynamic mode than the reference devices do but operate similarly in constant-resistance mode. Increasing the wire element length shows an increasing dynamic pressure range but a decreasing maximum sensitivity. The sensitivity is retained in high temperature mode, but the dynamic range is extended from about 10 Torr to about 700 Torr.

    Keywords
    HTCC, Pirani gauge, High temperature, Bond wires
    National Category
    Ceramics Other Electrical Engineering, Electronic Engineering, Information Engineering
    Research subject
    Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-356481 (URN)10.1016/j.sna.2018.10.008 (DOI)000456902600002 ()
    Available from: 2018-07-30 Created: 2018-07-30 Last updated: 2019-02-19Bibliographically approved
    5. Manufacturing Miniature Langmuir probes by Fusing Platinum Bond Wires
    Open this publication in new window or tab >>Manufacturing Miniature Langmuir probes by Fusing Platinum Bond Wires
    2015 (English)In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 25, no 10, article id 105012Article in journal (Refereed) Published
    Abstract [en]

    This paper reports on a novel method for manufacturing microscopic Langmuir probes with spherical tips from platinum bond wires for plasma characterization in microplasma sources by fusing. Here, the resulting endpoints, formed by droplets of a fused wire, are intended to act as a spherical Langmuir probe. For studying the fusing behavior, bond wires were wedge-bonded over a 2 mm wide slit, to emulate the final application, and fused at different currents and voltages. For electrical isolation, a set of wires were coated with a 4 µm thick layer of Parylene before they were fused. After fusing, the gap size, as well as the shape and area of the ends of the remaining stubs were measured. The yield of the process was also investigated, and the fusing event was studied using a high-speed camera for analyzing the dynamics of fusing. Four characteristic tip shapes were observed: spherical, semi-spherical, serpentine shaped and folded. The stub length leveled out at ~420µm. The fusing of the coated wires required a higher power for attaining a spherical shape. Finally, a Parylene coated bond wire was integrated into a stripline split-ring resonator (SSRR) microplasma source, and fused to form two Langmuir probes with spherical endpoints. These probes were used for measuring the I-V characteristics of a plasma generated by the SSRR. In a voltage range between -60 V and 60 V, the fused stubs exhibited the expected behavior of spherical Langmuir probes and will be considered for future integration.

    Keywords
    Langmuir probe; bond wire; fusing; microplasma source
    National Category
    Physical Sciences Engineering and Technology
    Research subject
    Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-251306 (URN)10.1088/0960-1317/25/10/105012 (DOI)000366827400028 ()
    Funder
    Swedish National Space BoardKnut and Alice Wallenberg Foundation
    Available from: 2015-04-15 Created: 2015-04-15 Last updated: 2018-08-03Bibliographically approved
    6. Effect of Resistive and Plasma Heating on the Specific Impulse of a Ceramic Cold Gas Thruster
    Open this publication in new window or tab >>Effect of Resistive and Plasma Heating on the Specific Impulse of a Ceramic Cold Gas Thruster
    Show others...
    2019 (English)In: Journal of microelectromechanical systems, ISSN 1057-7157, E-ISSN 1941-0158, Vol. 28, no 2, p. 235-244Article in journal (Refereed) Published
    Abstract [en]

    The research and development of small satellites has continued to expand over the last decades. However, the propulsion systems with adequate performance have persisted to be a great challenge. In this paper, the effects of three different heaters on the specific impulse and overall thrust efficiency of a cold gas microthruster are presented. They consisted of a conventional, printed resistive thick-film element, a freely suspended wire, and a stripline split-ring resonator microplasma source, and were integrated in a single device made from the high-temperature co-fired ceramics. The devices were evaluated in two setups, where the first measured thrust and the other measured shock cell geometry. In addition, the resistive elements were evaluated as gas temperature sensors. The microplasma source was found to provide the greatest improvement in both specific impulse and thrust efficiency, increasing the former from an un-heated level of 44–56 s when heating with a power of 1.1 W. This corresponded to a thrust efficiency of 55%, which could be compared with the results from the wire and printed heaters which were 51s and 18%, and 45s and 14%, respectively. The combined results also showed that imaging the shock cells of a plasma heated thruster was a simple and effective way to determine its performance, when compared to the traditional thrust balance method.

    Keywords
    Microthruster, HTCC, Resistive Heating, Plasma Heating, Specific Impulse, Shock Cells
    National Category
    Aerospace Engineering
    Research subject
    Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-356675 (URN)10.1109/JMEMS.2019.2893359 (DOI)000463623600008 ()
    Available from: 2018-08-02 Created: 2018-08-02 Last updated: 2019-04-25Bibliographically approved
    7. On the Applicability and Military Utility of Microsystems in Military Jet Engines
    Open this publication in new window or tab >>On the Applicability and Military Utility of Microsystems in Military Jet Engines
    (English)Manuscript (preprint) (Other academic)
    Keywords
    HTCC, jet engine control, applicability, military utility
    National Category
    Aerospace Engineering
    Identifiers
    urn:nbn:se:uu:diva-356691 (URN)
    Available from: 2018-08-03 Created: 2018-08-03 Last updated: 2018-08-03
  • 24.
    Sturesson, Peter
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC). Försvarshögskolan/Swedish National Defence College.
    Berglund, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Söderberg, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Persson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Fabrication of Suspended All-Metal Sensor Elements in Ceramic Laminates2016In: Proc. of Micronano System Workshop 2016, Lund, Sweden, May 17-18, 2016, 2016Conference paper (Other academic)
    Abstract [en]

    To target a wide range of high-temperature applications [1-4], the Ångström Space Technology Centre has added High-Temperature Co-fired Ceramics, HTTC, technology to its repertoire. Usually, this technology follows a processing scheme where thin sheets of green-body ceramics are metallized through screen printing and structured by embossing, punching or milling, before they are laminated and sintered to form components. A limitation with this, is the difficulty of realizing freely suspended metal structures, which is a disadvantage in, e.g., the fabrication of calorimetric sensors or electric field probes. In this work, the embedding of platinum wires in HTCC is explored experimentally, and demonstrated for use in pressure and plasma I-V sensing.

  • 25.
    Sturesson, Peter
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC). Försvarshögskolan/Swedish National Defence College.
    Bull, Peter
    Försvarshögskolan/Swedish National Defence College.
    On the Applicability and Military Utility of Microsystems in Military Jet EnginesManuscript (preprint) (Other academic)
  • 26.
    Sturesson, Peter
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC). Swedish National Defence College.
    Khaji, Zahra
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Knaust, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Thermomechanical behaviour and pressure sensing of ceramic wireless devices for high-temperature environments2014Conference paper (Refereed)
    Abstract [en]

    This paper reports on the design, fabrication and thermomechanical characterization of wirelessceramic devices, one with an integrated pressure sensor element. The project aims at developingmicrosystems for sensing in harsh environments where conventional electronic devices are restrained.Here, the devices are LC resonating circuits made from High-Temperature Co-fired Ceramic (HTCC)aluminium oxide green tapes. For the fabrication, the tapes were screen-printed with platinum paste,micromachined, stacked, laminated and fired. The additional sensor element was made from the samematerial and with the same processes, and contains a cavity sealed with a capacitive membrane.Thermomechanical characterization was made by investigating the bimorphic behaviour due to CTEmismatch as well as the resonance frequency of the devices as a function of mechanical displacement.Also, the resonance frequency as a function of pressure was demonstrated for the device with anintegrated pressure sensor node. The wireless readings were performed with a tuneable resonating loopantenna. The devices showed a relatively low quality factor value. The bimorphic behaviour is lowwith only small variations for temperatures up to 400°C. As for the mechanical displacement, theresonance frequency was only affected for thin devices at forced deformations that were larger thanthose observed as a function of temperature. For the device with an integrated pressure sensor, a clearpressure-induced frequency shift of 6785 ppm was observed at 1.5 bar. This indicates that the devicesare robust for high temperatures and also applicable for pressure readings. Future work will furtherexpand on high-temperature characterization of the devices.

  • 27.
    Sturesson, Peter
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC). Swedish National Defence College.
    Khaji, Zahra
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Knaust, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Thermomechanical rigidity of a wireless pressure senosr node for high-temperature applications2014In: 25th Micromechanics and Microsystems Europe workshop (MME 2014), 2014, P39 (4 pp), 2014Conference paper (Refereed)
    Abstract [en]

    Aimed for here, are microsensorequippednodes for environments too harsh for conventionalMEMS devices, especially with respect totemperature. Therefore, a prototype pressure sensorhas been made from micromachined, laminated andfired High-Temperature Co-fired Ceramic (HTCC)aluminium oxide green tapes. The Sensor is readwirelessly using LC resonating circuits made ofplatinum screen-printed on the tapes. In the specificwork package reported on here, the focus is on thethermomechanical characterization of the stackforming the device, since the bimorphic behavior dueto CTE mismatch of its constituents was believed toaffect the sensor performance. This part was conductedboth by optical profilometry of samples,ranging from 410 to 890 μm in thickness, heated to400°C, and by monitoring the frequency shift whenthe samples were subjected to three-point bending atroom temperature. With only negligible deformationsobserved for temperatures up to 400°C, a highthermomechanical rigidity was demonstrated.Furthermore, only when deformations larger thanthe thermomechanically induced ones were imposedon the thinnest samples, a shift in resonance frequencywas observed, indicating that the LC circuitrywill not be affected by the thermomechanicaldeformation of the sensor node. The sensor element,being a capacitor formed by a membrane sealing acavity and deflecting with changes in the ambientpressure, integrated in one of the samples, exhibiteda clear pressure-induced frequency shift of6785 ppm at 1.5 bar and room temperature. Inconclusion, the sensor node concept has been verifiedto have high thermal robustness.

  • 28.
    Sturesson, Peter
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC). Swedish Def Univ, Dept Mil Sci, Stockholm, Sweden.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Pirani Microgauge Fabricated of High-Temperature Co-fired Ceramics with Integrated Platinum Wires2019In: Sensors and Actuators A-Physical, ISSN 0924-4247, E-ISSN 1873-3069, Vol. 285, p. 8-16Article in journal (Refereed)
    Abstract [en]

    This paper presents the integration and pressure sensor operation of platinum bond wires in High-Temperature Co-fired alumina (HTCC). Devices were fabricated with a 50 μm diameter wire suspended across a 500 μm wide cavity in green-body state HTCC, electrically connected to screen printed alumina conductors. The substrate shrinkage during sintering to a cavity width of 400 μm causes the wire element to elevate from the cavity´s bottom surface. Resulting devices were compared with reference devices, containing screen-printed sensor elements, as Pirani gauges operated at 100 °C in constant-resistance mode, and in dynamic mode with a feeding current of 1 A in a pressure range from 10−4 Torr to atmospheric pressure. Also, devices with wire lengths between 500 and 3500 μm were operated and studied in constant-resistance and dynamic mode. Lastly, a device is demonstrated in operation at a mean temperature of 830 °C. The results include wire elements with a consistent elevation from their substrate surfaces, with irregularities along the wires. The wire devices exhibit a faster pressure response in dynamic mode than the reference devices do but operate similarly in constant-resistance mode. Increasing the wire element length shows an increasing dynamic pressure range but a decreasing maximum sensitivity. The sensitivity is retained in high temperature mode, but the dynamic range is extended from about 10 Torr to about 700 Torr.

  • 29.
    Sturesson, Peter
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC). Försvarshögskolan/Swedish National Defence College.
    Seton, Ragnar
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Persson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Effect of Resistive and Plasma Heating on the Specific Impulse of a Ceramic Cold Gas Thruster2019In: Journal of microelectromechanical systems, ISSN 1057-7157, E-ISSN 1941-0158, Vol. 28, no 2, p. 235-244Article in journal (Refereed)
    Abstract [en]

    The research and development of small satellites has continued to expand over the last decades. However, the propulsion systems with adequate performance have persisted to be a great challenge. In this paper, the effects of three different heaters on the specific impulse and overall thrust efficiency of a cold gas microthruster are presented. They consisted of a conventional, printed resistive thick-film element, a freely suspended wire, and a stripline split-ring resonator microplasma source, and were integrated in a single device made from the high-temperature co-fired ceramics. The devices were evaluated in two setups, where the first measured thrust and the other measured shock cell geometry. In addition, the resistive elements were evaluated as gas temperature sensors. The microplasma source was found to provide the greatest improvement in both specific impulse and thrust efficiency, increasing the former from an un-heated level of 44–56 s when heating with a power of 1.1 W. This corresponded to a thrust efficiency of 55%, which could be compared with the results from the wire and printed heaters which were 51s and 18%, and 45s and 14%, respectively. The combined results also showed that imaging the shock cells of a plasma heated thruster was a simple and effective way to determine its performance, when compared to the traditional thrust balance method.

  • 30.
    Söderberg Breivik, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Microscale Ceramic Pressure Sensor Element for a Carbon Isotope Analysis System for Planetary Exploration: – Design, Manufacturing and Characterization2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This master thesis examines the design, manufacturing and characterization of a miniaturized ceramic pressure gauge to be integrated into a system for carbon isotope analysis. Carbon isotope analysis can be used to find traces of extraterrestrial life.

    Screen printing, platinum bond wire threading, milling, lamination and sintering processes have been developed in order to manufacture a robust, temperature stable and chemically inert component potentially integratable to the carbon isotope analysis system. With use of the Pirani principle, which measures the pressure dependent thermal conductivity of air, promising results have been observed. A relative resistance change of 6 % within the pressure range of 1-10 Torr has been observed. This is comparable to, and even greater than, previous studies. The device has a good response for the desired pressure range. The device sensitivity was studied with different currents and geometric parameters. The results showed that the sensitivity is highly dependent on current and air volume.

    The work has been done at the Ångström Space Technology Centre –­­ a research group within the Ångström Laboratory, Uppsala University – which currently researches on microscale systems for, e.g., space exploration.

  • 31.
    Vargas Catalan, Ernesto
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Design and Manufacturing of a Rotationally Symmetric Cold Gas Nozzle in Silicon2012Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In this master thesis, the goal was to devise design patterns and a fabrication processfor manufacturing a 3-D rotationally symmetric converging-diverging cold gasmicronozzle in silicon.The report explains the theory of etching and the methods involved. The work beginswith calculations and simulations of the etching processes. The chosen etch techniqueutilizes so called microloading and reactive ion etching lag effects, which essentially arephenomena where the etch rate can be adjusted by breaking up mask features intosubpatterns, and the etch depth for a given recipe and time can be made to differlocally. The subpatterns consisted of very small rectangles and triangles withalternating concentration. Five different recipes for the reactive ion etching weretried, where the coil power, platen power, pressure, temperature and time wasvaried.Etch rates could be made to differ locally depending on the concentration ofsubpatterns within the mask feature. The etch rates were also affected by the recipeparameters such as coil power, platen power, and pressure. High coil and platenpower increased the etch rate, while high pressure reduced the etch rate. The platenpower also affected the surface roughness.A solution for reducing misalignment problems in the future for the fusion bondingprocess resulted in the proposed moiré patterns that were made to showmisalignments down to 0.2 μm.Through scanning electron microscopy, the Nozzle 5_4_2 was concluded to have themost rotationally symmetric cross section at both the throat and the outlet. It hasthroat diameter of 31.1 μm with a depth of 34.2 μm and an outlet diameter of146.4 μm with a depth of 113.2 μm

  • 32.
    Werr, Gabriel
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Khaji, Zahra
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Ohlin, Mathias
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Andersson, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Searle, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab. Department of Biomedical Engineering, National University of Singapore, Singapore 117583, Singapore.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC). Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Tenje, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Integrated thin film resistive sensors for in situ temperature measurements in an acoustic trap2019In: Acoustofluidics 2019: This annual meeting will be held in Twente, The Netherlands in 2019. This focused meeting is dedicated to exploring the science, engineering, and use of micro- to nanoscale acoustofluidics., 2019, p. 140-141Conference paper (Other academic)
    Abstract [en]

    This work presents an acoustic trap with integrated thin film sensors to monitor temperature variations during operation. The acoustic trap is wet-etched in glass with a thermally bonded glass lid and the thin-film sensors are integrated during fabrication. We evaluated the performance of the integrated temperature sensors and measured a temperature sensitivity of ±0.01 °C and confirmed that the read-out of the thin film sensors was not affected neither by the ionic conducitiviy of the solution nor the addition of microparticles into the acoustic trap. From the experiments we observed a temperature increase of the acoustic trap during operation as a result of the dissipative heating of the the piezoelectric element used to actuate the trap. We also showed that when external convective cooling was applied to the system, the temperature increase of the acoustic trap was higher than the temperature incresase of the piezoelectric element itself. This shows the importance of using integrated temperature sensors in acoustic trapping to monitor the environmental conditions.

  • 33.
    Åkerfeldt, Erika
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC).
    Improving thermal fracture resistance in ceramic microcomponents for spacecraft propulsion2018Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Because of thermal transients and gradients occurring upon rapid heating or cooling, microcomponents made from High-Temperature Co-fired Ceramics (HTCC) often fail at temperatures far below what the materials can withstand per se. This work investigates how resistance to thermal fracture in HTCC microcomponents can be increased by improving the component design, aiming at increasing the thermal performance of a microthruster with integrated heaters.

    The effect of four design parameters:  component and cavity geometries (circular or square), heater placement (central or peripheral), and addition of embedded platinum layers, on thermal fracture resistance was investigated experimentally through a study employing design of experiments.

    Components of different designs were manufactured, and their thermal fracture resistance tested by rapid heating until the occurrence of failure. Peripheral heater placement and presence of embedded platinum layers were seen to improve resistance to thermal fracture, whereas the shape of the component and the cavity did not significantly affect thermal performance.

    The most favourable design was then applied for a microthruster that was fabricated and evaluated with respect to thermal fracture resistance. The microthruster survived rapid heating up to 1461°C, and was operated as a cold gas microthruster at temperatures up to 772°C. None of these temperatures were limited by component failure, but by the component interface.

1 - 33 of 33
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