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  • 1.
    Abrahamsson, Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Hedlund, Magnus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Kamf, Tobias
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Bernhoff, Hans
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    High-Speed Kinetic Energy Buffer: Optimization of Composite Shell and Magnetic Bearings2014Ingår i: IEEE transactions on industrial electronics (1982. Print), ISSN 0278-0046, E-ISSN 1557-9948, Vol. 61, nr 6, s. 3012-3021Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents the design and optimization of a high-speed (30 000 r/min) kinetic energy storage system. The purpose of the device is to function as an energy buffer storing up to 867 Wh, primarily for utility vehicles in urban traffic. The rotor comprises a solid composite shell of carbon and glass fibers in an epoxy matrix, constructed in one curing. The shell is optimized using a combined analytical and numerical approach. The radial stress in the shell is kept compressive by integrating the electric machine, thereby avoiding delamination. Radial centering is achieved through eight active electromagnetic actuators. The actuator geometry is optimized using a direct coupling between SolidWorks, Comsol, and Matlab for maximum force over resistive loss for a given current density. The optimization results in a system with 300% higher current stiffness than the reference geometry with constant flux area, at the expense of 33% higher power loss. The actuators are driven by semipassive H bridges and controlled by an FPGA. Current control at 20 kHz with a noise of less than 5 mA (95% CI) is achieved, allowing position control at 4 kHz to be implemented.

  • 2.
    Abro, Mehwish
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Modelling the exfoliation of graphite for production of graphene2015Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The aim of my thesis is to make a theoretical model of data obtained from liquid-phase exfoliation of graphene. The production of graphene in the liquid phase exfoliation is a cost efficient method One part of this work is devotedto learn the method of production of graphene by the shear mixing technique from the graphite and to estimate some important parameters which are crucial for the process. Other part of my work is based on studying the liquid-phase exfoliation mechanism of graphene through ultrasonication technique. This method is time consuming as compared to shearmixing.

  • 3.
    Adrian, Ehrnebo
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Single Crystalline CVD Diamond Based Devices for Power Electronics Applications2014Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Chemical vapor deposited single-crystalline diamond has rare material properties such as thermal conductivity five times as high as copper, a wide band gap, a high breakdown field and high carrier mobilities. This makes it a very interesting material for high power, high frequency and high temperature applications.

    In this thesis work, metal oxide semiconductor (MOS) capacitors of diamond substrate were fabricated and analyzed. The MOS capacitor is a building block of the metal oxide semiconductor field effect transistor (MOSFET). Capacitance-voltage (C-V) measurements can provide useful information of the operation of a MOS. Electrical characterization by C-V and current-voltage (I-V) measurements at temperatures ranging from 20 to 150 degrees Celsius were performed on the MOS capacitors to examine flatband and threshold voltages, oxide charge, and oxide thickness.

    At elevated temperatures, low frequency C-V curves with threshold voltages of approximately 5 V were obtained for MOS capacitors consisting of aluminum gates, a 30 nm layer of aluminum oxide, and boron doped diamond with acceptor concentration 3.1 x 1017 cm-3. The C-V measurements also showed large variations in flatband voltage for different contacts of the MOS capacitor, indicating the presence of oxide charge. Oxide thickness was also extracted from the C-V measurements, typically showing thicknesses around 15-19 nm.

    Also in this  thesis, an alternative method for reducing the electric field strength around the edges of the contact of a Schottky diode has been examined. This method consists of alternating the geometry by etching the semiconductor where the contact is to be placed. Simulations performed in Comsol Multiphysics showed that a reduction of the field strength of approximately 30 % at the contacts could be achieved by etching the substrate.

  • 4.
    Ahlberg, Patrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Graphene Implementation Study in Semiconductor Processing2016Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Graphene, with its two-dimensional nature and unique properties, has for over a decade captured enormous interests in both industry and academia. This work tries to answer the question of what would happen to graphene when it is subjected to various processing conditions and how this would affect the graphene functionality. The focus is placed on its ability to withstand different thin-film deposition environments with regard to the implementation of graphene in two application areas: as a diffusion barrier and in electronic devices.

    With single-layer graphene films grown in-house by means of chemical vapor deposition (CVD), four techniques among the well-established thin-film deposition methods are studied in detail: atomic layer deposition (ALD), evaporation, sputter-deposition and spray-deposition. And in this order, these methods span a large range of kinetic impact energies from low to high. Graphene is known to have a threshold displacement energy of 22 eV above which carbon atoms are ejected from the lattice. Thus, ALD and evaporation work with energies below this threshold, while sputtering and spraying may involve energies above. The quality of the graphene films undergone the various depositions is mainly evaluated using Raman spectroscopy.

    Spray deposition of liquid alloy Ga-In-Sn is shown to require a stack of at least 4 layers of graphene in order to act as an effective barrier to the Ga diffusion after the harsh spray-processing. Sputter-deposition is found to benefit from low substrate temperature and high chamber pressure (thereby low kinetic impact energy) so as to avoid damaging the graphene. Reactive sputtering should be avoided. Evaporation is non-invasiveness with low kinetic impact energy and graphene can be subjected to repeated evaporation and removal steps without losing its integrity. With ALD, the effects on graphene are of different nature and they are investigated in the field-effect-transistor (FET) configuration. The ALD process for deposition of Al2O3 films is found to remove undesired dopants from the prior processing and the Al2O3 films are shown to protect the graphene channel from doping by oxygen. When the substrate is turned hydrophobic by chemical treatment prior to graphene transfer-deposition, a unipolar transistor behavior is obtained.

    Delarbeten
    1. A two-in-one process for reliable graphene transistors processed with photolithography
    Öppna denna publikation i ny flik eller fönster >>A two-in-one process for reliable graphene transistors processed with photolithography
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    2015 (Engelska)Ingår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 107, nr 20, artikel-id 203104Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Research on graphene field-effect transistors (GFETs) has mainly relied on devices fabricated using electron-beam lithography for pattern generation, a method that has known problems with polymer contaminants. GFETs fabricated via photo-lithography suffer even worse from other chemical contaminations, which may lead to strong unintentional doping of the graphene. In this letter, we report on a scalable fabrication process for reliable GFETs based on ordinary photo-lithography by eliminating the aforementioned issues. The key to making this GFET processing compatible with silicon technology lies in a two-in-one process where a gate dielectric is deposited by means of atomic layer deposition. During this deposition step, contaminants, likely unintentionally introduced during the graphene transfer and patterning, are effectively removed. The resulting GFETs exhibit current-voltage characteristics representative to that of intrinsic non-doped graphene. Fundamental aspects pertaining to the surface engineering employed in this work are investigated in the light of chemical analysis in combination with electrical characterization.

    Nationell ämneskategori
    Fysik Teknik och teknologier
    Identifikatorer
    urn:nbn:se:uu:diva-269191 (URN)10.1063/1.4935985 (DOI)000365688700049 ()
    Forskningsfinansiär
    Knut och Alice Wallenbergs Stiftelse, 2011.0113, 2011.0082Stiftelsen för strategisk forskning (SSF), SE13-0061Vetenskapsrådet, 621-2014-5591
    Tillgänglig från: 2015-12-14 Skapad: 2015-12-14 Senast uppdaterad: 2017-12-01Bibliografiskt granskad
    2. Interface Dependent Effective Mobility in Graphene Field Effect Transistors
    Öppna denna publikation i ny flik eller fönster >>Interface Dependent Effective Mobility in Graphene Field Effect Transistors
    2018 (Engelska)Ingår i: Journal of Electronic Materials, ISSN 0361-5235, E-ISSN 1543-186X, Vol. 47, nr 3, s. 1757-1761Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    By pretreating the substrate of a graphene field-effect transistor (G-FET), a stable unipolar transfer characteristic, instead of the typical V-shape ambipolar behavior, has been demonstrated. This behavior is achieved through functionalization of the SiO2/Si substrate that changes the SiO2 surface from hydrophilic to hydrophobic, in combination with postdeposition of an Al2O3 film by atomic layer deposition (ALD). Consequently, the back-gated G-FET is found to have increased apparent hole mobility and suppressed apparent electron mobility. Furthermore, with addition of a top-gate electrode, the G-FET is in a double-gate configuration with independent top- or back-gate control. The observed difference in mobility is shown to also be dependent on the top-gate bias, with more pronounced effect at higher electric field. Thus, the combination of top and bottom gates allows control of the G-FET's electron and hole mobilities, i.e., of the transfer behavior. Based on these observations, it is proposed that polar ligands are introduced during the ALD step and, depending on their polarization, result in an apparent increase of the effective hole mobility and an apparent suppressed effective electron mobility.

    Nationell ämneskategori
    Teknik och teknologier Elektroteknik och elektronik
    Forskningsämne
    Teknisk fysik med inriktning mot elektronik
    Identifikatorer
    urn:nbn:se:uu:diva-284924 (URN)10.1007/s11664-017-6023-6 (DOI)000424341700002 ()
    Forskningsfinansiär
    Knut och Alice Wallenbergs Stiftelse, 2011.0082Vetenskapsrådet, 2014-5591
    Tillgänglig från: 2016-04-19 Skapad: 2016-04-19 Senast uppdaterad: 2018-04-11Bibliografiskt granskad
    3. Defect formation in graphene during low-energy ion bombardment
    Öppna denna publikation i ny flik eller fönster >>Defect formation in graphene during low-energy ion bombardment
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    2016 (Engelska)Ingår i: APL Materials, ISSN 2166-532X, Vol. 4, nr 4, artikel-id 046104Artikel i tidskrift, Letter (Refereegranskat) Published
    Abstract [en]

    This letter reports on a systematic investigation of sputter induced damage in graphene caused by low energy Ar+ ion bombardment. The integral numbers of ions per area (dose) as well as their energies are varied in the range of a few eV's up to 200 eV. The defects in the graphene are correlated to the dose/energy and different mechanisms for the defect formation are presented. The energetic bombardment associated with the conventional sputter deposition process is typically in the investigated energy range. However, during sputter deposition on graphene, the energetic particle bombardment potentially disrupts the crystallinity and consequently deteriorates its properties. One purpose with the present study is therefore to demonstrate the limits and possibilities with sputter deposition of thin films on graphene and to identify energy levels necessary to obtain defect free graphene during the sputter deposition process. Another purpose is to disclose the fundamental mechanisms responsible for defect formation in graphene for the studied energy range.

    Nationell ämneskategori
    Materialkemi Nanoteknik
    Identifikatorer
    urn:nbn:se:uu:diva-284702 (URN)10.1063/1.4945587 (DOI)000375846100007 ()
    Forskningsfinansiär
    Knut och Alice Wallenbergs Stiftelse, 2011.0082Vetenskapsrådet, 2014-5591 2014-6463
    Tillgänglig från: 2016-04-19 Skapad: 2016-04-19 Senast uppdaterad: 2017-01-25Bibliografiskt granskad
    4. Toward synthesis of oxide films on graphene with sputtering based processes
    Öppna denna publikation i ny flik eller fönster >>Toward synthesis of oxide films on graphene with sputtering based processes
    2016 (Engelska)Ingår i: Journal of Vacuum Science and Technology B: Nanotechnology and Microelectronics, ISSN 2166-2746, E-ISSN 2166-2754Artikel i tidskrift (Refereegranskat) Submitted
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:uu:diva-284706 (URN)
    Externt samarbete:
    Tillgänglig från: 2016-04-19 Skapad: 2016-04-19 Senast uppdaterad: 2017-11-30
    5. Graphene as a Diffusion Barrier in Galinstan-Solid Metal Contacts
    Öppna denna publikation i ny flik eller fönster >>Graphene as a Diffusion Barrier in Galinstan-Solid Metal Contacts
    Visa övriga...
    2014 (Engelska)Ingår i: IEEE Transactions on Electron Devices, ISSN 0018-9383, E-ISSN 1557-9646, Vol. 61, nr 8, s. 2996-3000Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    This paper presents the use of graphene as a diffusion barrier to a eutectic Ga-In-Sn alloy, i.e., galinstan, for electrical contacts in electronics. Galinstan is known to be incompatible with many conventional metals used for electrical contacts. When galinstan is in direct contact with Al thin films, Al is readily dissolved leading to the formation of Al oxides present on the surface of the galinstan droplets. This reaction is monitored ex situ using several material analysis methods as well as in situ using a simple circuit to follow the time-dependent resistance variation. In the presence of a multilayer graphene diffusion barrier, the Al-galinstan reaction is effectively prevented for galinstan deposited by means of drop casting. When deposited by spray coating, the high-impact momentum of the galinstan droplets causes damage to the multilayer graphene and the Al-galinstan reaction is observed at some defective spots. Nonetheless, the graphene barrier is likely to block the formation of Al oxides at the Al/galinstan interface leading to a stable electrical current in the test circuit.

    Nationell ämneskategori
    Annan elektroteknik och elektronik Nanoteknik
    Forskningsämne
    Teknisk fysik med inriktning mot elektronik; Teknisk fysik med inriktning mot mikrosystemteknik
    Identifikatorer
    urn:nbn:se:uu:diva-229503 (URN)10.1109/TED.2014.2331893 (DOI)000342906200056 ()
    Tillgänglig från: 2014-08-10 Skapad: 2014-08-10 Senast uppdaterad: 2017-12-05Bibliografiskt granskad
    6. Scalable residue-free graphene for surface-enhanced Raman scattering
    Öppna denna publikation i ny flik eller fönster >>Scalable residue-free graphene for surface-enhanced Raman scattering
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    2016 (Engelska)Ingår i: Carbon, ISSN 0008-6223, E-ISSN 1873-3891, Vol. 98, s. 567-571Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    A room-temperature polymer-assisted transfer process is developed for large-area, single-layer graphene grown by means of chemical vapor deposition (CVD). This process leads to transferred graphene layers free of polymer contamination. The absence of polymer residues boosts the surface-enhanced Raman scattering (SERS) of the CVD graphene with gold nanoparticles (Au NPs) deposited atop by evaporation. The SERS enhancement of the CVD graphene reaches similar to 120 for the characteristic 2D peak of graphene, the highest enhancement factor achieved to date, when the Au NPs are at the threshold of percolation. Our simulation supported by experiment suggests that the polymer residues persistently present on the graphene transferred by the conventional polymer-assisted method are equivalent to an ultrathin film of less than 1 nm thickness. The presence of polymer residues drastically reduces SERS due to the separation of the Au NPs from the underlying graphene. The scalability of CVD graphene opens up for the possibility of graphene-based SERS sensors.

    Nationell ämneskategori
    Fysik Teknik och teknologier
    Identifikatorer
    urn:nbn:se:uu:diva-269192 (URN)10.1016/j.carbon.2015.11.043 (DOI)000367233000070 ()
    Forskningsfinansiär
    Knut och Alice Wallenbergs Stiftelse, 2011.0113Knut och Alice Wallenbergs Stiftelse, 2011.0082Stiftelsen för strategisk forskning (SSF), SE13-0061Vetenskapsrådet, 621-2014-5591
    Tillgänglig från: 2015-12-14 Skapad: 2015-12-14 Senast uppdaterad: 2017-12-01Bibliografiskt granskad
  • 5.
    Ahlberg, Patrik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Seung, Hee Jeong
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Jiao, Mingzhi
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Wu, Zhigang
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Zhang, Shi-Li
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Zhang, Zhi-Bin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Graphene as a Diffusion Barrier in Galinstan-Solid Metal Contacts2014Ingår i: IEEE Transactions on Electron Devices, ISSN 0018-9383, E-ISSN 1557-9646, Vol. 61, nr 8, s. 2996-3000Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents the use of graphene as a diffusion barrier to a eutectic Ga-In-Sn alloy, i.e., galinstan, for electrical contacts in electronics. Galinstan is known to be incompatible with many conventional metals used for electrical contacts. When galinstan is in direct contact with Al thin films, Al is readily dissolved leading to the formation of Al oxides present on the surface of the galinstan droplets. This reaction is monitored ex situ using several material analysis methods as well as in situ using a simple circuit to follow the time-dependent resistance variation. In the presence of a multilayer graphene diffusion barrier, the Al-galinstan reaction is effectively prevented for galinstan deposited by means of drop casting. When deposited by spray coating, the high-impact momentum of the galinstan droplets causes damage to the multilayer graphene and the Al-galinstan reaction is observed at some defective spots. Nonetheless, the graphene barrier is likely to block the formation of Al oxides at the Al/galinstan interface leading to a stable electrical current in the test circuit.

  • 6. Ahlgren Peters, Adam
    et al.
    Söderholm, Robin
    Wahlmark, Rickard
    Analog gitarrförstärkare: med rörliknande egenskaper2017Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
  • 7.
    Ahlström, Erik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Åsktransienter och överspänningar: En spänningsfylld simulering av elkraftsystemet vid Forsmark 32014Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    A power system will inevitably be subjected to transient overvoltages, most often produced by switching operations and lightning strikes. These transient overvoltages may harm sensitive equipment without sufficient protection, but it is not an easy task to predict what transients may occur or how they affect the system. A fault occurred in a low voltage system at Forsmark 2012 and overvoltages from lightning were concluded as the probable cause. The three aims with this thesis are to develop and test a model of the power system at Forsmark 3, analyse the transient behaviour of the system when subjected to lightning surges and identify critical parameters, and lastly to provide a tool for investigating the protection of the system. The modelling and simulations were performed in the freely available simulation program LT Spice. Challenges and difficulties have been to obtain parameter values for components that are relevant for the high frequencies produced by the short rise time in lightning surges. The main conclusions are: the maximum current in the lightning discharge has the largest impact on the system voltages and surges in the external grid can produce standing waves in the system, causing significant overvoltages even in low voltage systems. The simulations produced larger overvoltages than would occur in a real system, which also would dampen the high frequency signals to a larger extent. Further work to obtain models better suited for high frequency simulation is suggested.

  • 8.
    Ahmad, Mohd Riduan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära. Universiti Teknikal Malaysia Melaka.
    Interaction of Lightning Flashes with Wireless Communication Networks: Special Attention to Narrow Bipolar Pulses2014Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    In this thesis, the features of electric field signatures of narrow bipolar pulses (NBPs) generated by cloud flashes are investigated and their effects on wireless communication systems are studied. A handful amount of NBPs (14.5%) have been observed to occur as part of cloud-to-ground flashes in South Malaysia. Occurrence of NBPs in Sweden has been reported for the first time in this thesis. The electric field waveform characteristics of NBPs as part of cloud-to-ground flashes were similar to isolated NBPs found in Sweden and South Malaysia and also to those isolated NBPs reported by previous studies from various geographical areas. This is a strong indication that their breakdown mechanisms are similar at any latitudes regardless of geographical areas.

    A comparative study on the occurrence of NBPs and other forms of lightning flashes across various geographical areas ranging from northern regions to the tropics is presented. As the latitude decreased from Uppsala, Sweden (59.8°N) to South Malaysia (1.5°N), the percentage of NBP emissions relative to the total number of lightning flashes increased significantly from 0.13% to 12%. Occurrences of positive NBPs were more common than negative NBPs at all observed latitudes. However, as latitudes decreased, the negative NBP emissions increased significantly from 20% (Sweden) to 45% (South Malaysia). Factors involving mixed-phase region elevations and vertical extents of thundercloud tops are invoked to explain the observed results. These factors are fundamentally latitude dependent.

    In this thesis, the interaction between microwave radiations emitted by cloud-to-ground and cloud flashes events and bits transmission in wireless communication networks are also presented. To the best of our knowledge, this is the first time such effects are investigated in the literature. Narrow bipolar pulses were found to be the strongest source of interference that interfered with the bits transmission.

    Delarbeten
    1. Signatures of Narrow Bipolar Pulses as Part of Cloud-to-Ground Flashes in Tropical Thunderstorms
    Öppna denna publikation i ny flik eller fönster >>Signatures of Narrow Bipolar Pulses as Part of Cloud-to-Ground Flashes in Tropical Thunderstorms
    2014 (Engelska)Ingår i: Journal of Atmospheric and Solar-Terrestrial Physics, ISSN 1364-6826, E-ISSN 1879-1824Artikel i tidskrift (Refereegranskat) Submitted
    Nyckelord
    Narrow bipolar pulse; Return stroke; Tropical thunderstorm.
    Nationell ämneskategori
    Meteorologi och atmosfärforskning Teknik och teknologier
    Forskningsämne
    Teknisk fysik med inriktning mot atmosfäriska urladdningar
    Identifikatorer
    urn:nbn:se:uu:diva-233624 (URN)
    Tillgänglig från: 2014-10-07 Skapad: 2014-10-07 Senast uppdaterad: 2017-12-05
    2. Narrow bipolar pulses and associated microwave radiation
    Öppna denna publikation i ny flik eller fönster >>Narrow bipolar pulses and associated microwave radiation
    2013 (Engelska)Konferensbidrag, Publicerat paper (Refereegranskat)
    Ort, förlag, år, upplaga, sidor
    Stockholm: , 2013
    Nationell ämneskategori
    Teknik och teknologier
    Forskningsämne
    Teknisk fysik med inriktning mot elektricitetslära
    Identifikatorer
    urn:nbn:se:uu:diva-212898 (URN)
    Konferens
    Progress in Electromagnetics Research Symposium
    Tillgänglig från: 2013-12-16 Skapad: 2013-12-16 Senast uppdaterad: 2015-01-23
    3. Electric Field Signature of Narrow Bipolar Pulse Observed in Sweden
    Öppna denna publikation i ny flik eller fönster >>Electric Field Signature of Narrow Bipolar Pulse Observed in Sweden
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    2014 (Engelska)Ingår i: Atmospheric research, ISSN 0169-8095, E-ISSN 1873-2895Artikel i tidskrift (Refereegranskat) Submitted
    Nyckelord
    Electric field; Narrow bipolar pulse; Sweden.
    Nationell ämneskategori
    Meteorologi och atmosfärforskning Teknik och teknologier
    Forskningsämne
    Teknisk fysik med inriktning mot atmosfäriska urladdningar
    Identifikatorer
    urn:nbn:se:uu:diva-233636 (URN)
    Tillgänglig från: 2014-10-07 Skapad: 2014-10-07 Senast uppdaterad: 2017-12-05
    4. Latitude Dependence of Narrow Bipolar Pulse Emissions
    Öppna denna publikation i ny flik eller fönster >>Latitude Dependence of Narrow Bipolar Pulse Emissions
    Visa övriga...
    2015 (Engelska)Ingår i: Journal of Atmospheric and Solar-Terrestrial Physics, ISSN 1364-6826, E-ISSN 1879-1824, Vol. 128, s. 40-45Artikel i tidskrift (Refereegranskat) Published
    Nyckelord
    Latitude; Narrow bipolar pulse; Thunderstorm.
    Nationell ämneskategori
    Meteorologi och atmosfärforskning Teknik och teknologier
    Forskningsämne
    Teknisk fysik med inriktning mot atmosfäriska urladdningar
    Identifikatorer
    urn:nbn:se:uu:diva-233638 (URN)10.1016/j.jastp.2015.03.005 (DOI)000355717500005 ()
    Tillgänglig från: 2014-10-07 Skapad: 2014-10-07 Senast uppdaterad: 2017-12-05Bibliografiskt granskad
    5. Similarity between the Initial Breakdown Pulses of Negative Ground Flash and Narrow Bipolar Pulses
    Öppna denna publikation i ny flik eller fönster >>Similarity between the Initial Breakdown Pulses of Negative Ground Flash and Narrow Bipolar Pulses
    2014 (Engelska)Ingår i: 2014 INTERNATIONAL CONFERENCE ON LIGHTNING PROTECTION (ICLP), IEEE conference proceedings, 2014, s. 810-813Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    In this paper, temporal characteristics of several initial electric field pulses of preliminary breakdown process (PBP) from very close negative cloud-to-ground (CG) flashes are compared to close narrow bipolar pulses (NBPs) to observe any similarity that may exists. Interestingly, we found that the initial PBP pulses are similar to close NBP with zero crossing time less than 5 mu s, do not preceded by any slow field change and followed by pronounce static component. As NBPs are believed to be a result of relativistic runaway electron avalanches discharge, this finding is an indication that the initial electric field pulses of PBP are perhaps the result of the same discharge mechanism.

    Ort, förlag, år, upplaga, sidor
    IEEE conference proceedings, 2014
    Nyckelord
    Narrow bipolar pulse; Preliminary breakdown pulse; Relativistic runaway electron avalanches.
    Nationell ämneskategori
    Meteorologi och atmosfärforskning Teknik och teknologier
    Forskningsämne
    Teknisk fysik med inriktning mot atmosfäriska urladdningar
    Identifikatorer
    urn:nbn:se:uu:diva-233639 (URN)000358572100153 ()978-1-4799-3544-4 (ISBN)
    Konferens
    International Conference on Lightning Protection (ICLP), OCT 11-18, 2014, Tsinghua Univ, Shanghai, PEOPLES R CHINA
    Tillgänglig från: 2014-10-07 Skapad: 2014-10-07 Senast uppdaterad: 2015-09-03Bibliografiskt granskad
    6. Lightning interference in multiple antennas wireless communication systems
    Öppna denna publikation i ny flik eller fönster >>Lightning interference in multiple antennas wireless communication systems
    Visa övriga...
    2012 (Engelska)Ingår i: Journal of Lightning Research, ISSN 1652-8034, Vol. 4, s. 155-165Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    This paper analyzes the interference of lightning flashes with multiple antennas wireless communicationsystems operating in the microwave band at 2.4 GHz and 5.2 GHz. A bit error rate (BER) measurement method was usedto evaluate BER and packet error rate (PER) during 5 heavy thunderstorms on January 25 and March 17 to 20, 2011,respectively. In addition, BER measurements also were done on January 21 and March 30, 2011 under fair weather (FW)conditions providing a baseline for comparison. The Transmitter-Receiver separation was fixed at 10 meter with line-ofsight(LOS) consideration. We infer that lightning interfered with the transmitted digital pulses which resulted in a higherrecorded BER. The maximum recorded BER was 9.9·10-1 and the average recorded BER and PER were 2.07·10-2 and2.44·10-2 respectively during the thunderstorms with the average fair weather BER and PER values under the influence ofadjacent channel interference (ACI) and co-channel interference (CCI) being 1.75·10-5 and 7.35·10-6 respectively. Weconclude that multiple antennas wireless communication systems operating at the microwave frequency can besignificantly interfered by lightning.

    Ort, förlag, år, upplaga, sidor
    Bentham open, 2012
    Nationell ämneskategori
    Meteorologi och atmosfärforskning Teknik och teknologier
    Forskningsämne
    Teknisk fysik med inriktning mot atmosfäriska urladdningar
    Identifikatorer
    urn:nbn:se:uu:diva-190902 (URN)
    Tillgänglig från: 2013-01-09 Skapad: 2013-01-09 Senast uppdaterad: 2016-02-03
    7. Interference from cloud-to-ground and cloud flashes in wireless communication system
    Öppna denna publikation i ny flik eller fönster >>Interference from cloud-to-ground and cloud flashes in wireless communication system
    2014 (Engelska)Ingår i: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 113, s. 237-246Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    In this study, cloud-to-ground (CG) flash and intra-cloud (IC) flash events that interfere with the transmission of bits in wireless communication system operating at 2.4 GHz were analyzed. Bit error rate (BER) and consecutive lost datagram (CLD) measurement methods were used to evaluate BER and burst error from 3 tropical thunderstorms on November 27, 28, and 29 during 2012 northeastern monsoon in Malaysia. A total of 850 waveforms from the electric field change recording system were recorded and examined. Out of these, 94 waveforms of very fine structure were selected which matched perfectly with the timing information of the recorded BER. We found that both CG and IC flashes interfered significantly with the transmission of bits in wireless communication system. The severity of the interference depends mainly on two factors namely the number of pulses and the amplitude intensity of the flash. The interference level becomes worst when the number of pulses in a flash increases and the amplitude intensity of pulses in a flash intensifies. During thunderstorms, wireless communication system has experienced mostly intermittent interference due to burst error. Occasionally, in the presence of very intense NBP event, wireless communication system could experience total communication lost. In CG flash, it can be concluded that PBP is the major. source of interference that interfered with the bits transmission and caused the largest burst error. In IC flash, we found that the typical IC pulses interfered the bits transmission in the same way as PBP and mixed events in CG flash and produced comparable and in some cases higher amount of burst error. NBP has been observed to interfere the bits transmission more severely than typical IC and CG flashes and caused the most severe burst error to wireless communication system.

    Nyckelord
    Bit error rate, Cloud flash, Cloud-to-ground flash, Interference, Microwave radiation, Wireless system
    Nationell ämneskategori
    Elektroteknik och elektronik
    Identifikatorer
    urn:nbn:se:uu:diva-228679 (URN)10.1016/j.epsr.2014.03.022 (DOI)000337554200032 ()
    Tillgänglig från: 2014-07-22 Skapad: 2014-07-21 Senast uppdaterad: 2017-12-05Bibliografiskt granskad
  • 9.
    An, Hongbin
    et al.
    Huazhong Univ Sci & Technol, State Key Lab Digital Mfg Equipment & Technol, Wuhan 430074, Hubei, Peoples R China.
    Chen, Liangzhou
    Huazhong Univ Sci & Technol, State Key Lab Digital Mfg Equipment & Technol, Wuhan 430074, Hubei, Peoples R China.
    Liu, Xiaojun
    Huazhong Univ Sci & Technol, State Key Lab Digital Mfg Equipment & Technol, Wuhan 430074, Hubei, Peoples R China.
    Zhao, Bin
    Huazhong Univ Sci & Technol, State Key Lab Digital Mfg Equipment & Technol, Wuhan 430074, Hubei, Peoples R China.
    Ma, Donglin
    Huazhong Univ Sci & Technol, Sch Opt & Elect Informat, Wuhan 430074, Hubei, Peoples R China.
    Wu, Zhigang
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik. Huazhong Univ Sci & Technol, State Key Lab Digital Mfg Equipment & Technol, Wuhan 430074, Hubei, Peoples R China.
    A method of manufacturing microfluidic contact lenses by using irreversible bonding and thermoforming2018Ingår i: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 28, nr 10, artikel-id 105008Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, we present the development of microfluidic contact lenses, which is based on the advantages of wearable microfluidics and can have great potential in the ophthalmology healthcare field. The development consists of two parts; the manufacturing process and the usability tests of the devices. In the manufacturing process, we firstly extended silane coupling and surface modification to irreversibly bond plastic membranes with microchannel-molded silicone rubber, to form the plastic-PDMS plane assemblies, and then molded the plane into a contact lens by thermoforming. We systematically investigated the effects of thermoforming factors, heating temperatures and the terrace die's sphere radius on channels by using the factorial experiment design. In addition, various tests were conducted to verify the usability of the devices. Through blockage and leakage tests, the devices were proved to be feasible, with no channel-blockages and could stand high pressures. Through a wearing test, the contact lenses were confirmed to be harmless on the living body. Furthermore, by performing the manipulating test, the device was proved to be liquid-controllable. These works provide a foundation for the applications of microfluidic contact lenses in ophthalmology.

  • 10. Andersson, Hjalmar
    et al.
    Zdansky Cottle, Leo
    Claesson, Melker
    Karlsson, Nils
    Stenhammar, Oscar
    Insamling av drift- och produktionsdata från energiteknik vid Ihus anläggning på Vaksala-Eke2019Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    För att minska den globala uppvärmningen bär utbyggnaden av förnybar energiproduktion en stor vikt i dagens samhälle. Av den anledningen är det av stor betydelse som nya tekniker för energiproduktion testas. För att undersöka huruvida dessa tekniker är effektiva och lönsamma är det viktigt att deras produktionsdata publiceras och görs tillgänglig för allmänheten. Det är anledningen till att det här projektet beställts från Ihus via STUNS energi.

    Projektidén var att samla in högfrekvent uppmätt produktionsdata från en soltracker, ett vindkraftverk och ett batterilager. Dessutom skulle väderdata samlas från en väderstation och solinstrålningsmätare för att sedan offentliggöra datan via STUNS Energiportal.

    För genomförandet av projektet användes en enklare dator för att ta emot information från olika sensorer. För att kommunicera med enheterna användes olika standardiserade kommunikationsprotokoll. Enheterna konfigurerades och kopplades in i datorn. Den insamlade datan bearbetades med en programmerad kod. Programmet sände iväg datan till en molnlagringsplattform för att sedan publicera den.

    Uppkoppling mot soltrackerns växelriktare samt pyranometern lyckades. Den insamlade informationen från de två enheterna publicerades sedan på Energiportalen. Väderstationen producerade data men kommunikation med det ursprungligt tänkta protokollet lyckades inte att upprättas. Genom ett annat protokoll erhölls värden, men inte genom den implementerade koden. Dessutom uppstod problem med batterilagret och vindkraftverket. Ingen information lyckades hämtas från någon av dem.

    I projektets gång har det samlats in mätpunkter var femte sekund för respektive enhet. Utifrån det erhållna resultatet kan de konstateras att vid högfrekvent insamling av väder- och produktionsdata, blir viktig information tydligare för vardera energiproduktionsenhet. Denna information kan gå förlorad vid lågfrekvent datainsamling. Det beror på vädrets hastiga fluktuation. En lågfrekventare datainsamling ger således en sämre uppfattning av hur värdena egentligen ändras med tiden.

  • 11.
    Andersson, Martin
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Wilson, Anton
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Hjort, Klas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Klintberg, Lena
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    A microfluidic relative permittivity sensor for feedback control of carbon dioxide expanded liquid flows2019Ingår i: Sensors and Actuators A-Physical, ISSN 0924-4247, E-ISSN 1873-3069, Vol. 285, s. 165-172Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Binary CO2-alcohol mixtures, such as CO2-expanded liquids (CXLs), are promising green solvents for reaching higher performance in flow chemistry and separation processing. However, their compressibility and high working pressure makes handling challenging. These mixtures allow for a tuneable polarity but, to do so, requires precise flow control. Here, a high-pressure tolerant microfluidic system containing a relative permittivity sensor and a mixing chip is used to actively regulate the relative permittivity of these fluids and indirectly—composition. The sensor is a fluid-filled plate capacitor created using embedded 3D-structured thin films and has a linearity of 0.9999, a sensitivity of 4.88 pF per unit of relative permittivity, and a precision within 0.6% for a sampling volume of 0.3 μL. Composition and relative permittivity of CO2-ethanol mixtures were measured at 82 bar and 21 °C during flow. By flow and dielectric models, this relationship was found to be described by the pure components and a quadratic mixing rule with an interaction parameter, kij, of -0.63 ± 0.02. Microflows with a relative permittivity of 1.7–21.4 were generated, and using the models, this was found to correspond to compositions of 6–90 mol % ethanol in CO2. With the sensor, a closed loop control system was realised and CO2-ethanol flows were tuned to setpoints of the relative permittivity in 30 s.

  • 12. Andersson, Oskar
    Savonius wind turbine innovation integrated in a constructed nano grid system2019Självständigt arbete på grundnivå (yrkesexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    A nanogrid system for supplying neutrino detectors on Antarctica with electricity is

    designed and built. The nanogrid system could later on be implemented in various

    configurations where suppling electricity to neutrino detectors is one area of use.

    The energy system that is acting on site in Antarctica is based around solar panels

    to provide power to the measuring equipment. However, providing electricity in

    such a way is not optimal due to its failure in delivering electricity at times. A

    nanogrid that can stand the demands of constant energy supply to the

    measurement station are therefore constructed. The energy sources that are

    integrated into the nanogrid are an innovation in vertical axis wind turbine and

    photovoltaics. The wind turbine innovation is tested under real conditions for the

    first time. In the constructed nanogrid, there are also integrated energy storage

    consisting of battery cells that are coupled together to a coherent unit.

    Measurement equipment is also implemented for analyzation of acting wind turbine

    as well as different types of safety equipment for redundancy in the system. In the

    nanogrid, a rectifier for AC to DC transformation is constructed. An inverter for DC

    to AC transformation is also implemented for supplying electricity to the

    equipment that are acting on the grid.

    The system is tested under real conditions. The whole system could observe

    partially function and configurated well to the various parts of the whole system.

    Further optimisation of some parts of the system from the prototype is needed.

  • 13.
    Anderås, Emil
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Advanced MEMS Pressure Sensors Operating in Fluids2012Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Today’s MEMS technology allows manufacturing of miniaturized, low power sensors that sometimes exceeds the performance of conventional sensors. The pressure sensor market today is dominated by MEMS pressure sensors.

    In this thesis two different pressure sensor techniques are studied. The first concerns ways to improve the sensitivity in the most commonly occurring pressure sensor, namely such based on the piezoresistive technique. Since the giant piezoresistive effect was observed in silicon nanowires, it was assumed that a similar effect could be expected in nano-thin silicon films. However, it turned out that the conductivity was extremely sensitive to substrate bias and could therefore be controlled by varying the backside potential. Another important parameter was the resistivity time drift. Long time measurements showed a drastic variation in the resistance. Not even after several hours of measurement was steady state reached. The drift is explained by hole injection into the buried oxide as well as existence of mobile charges. The piezoresistive effect was studied and shown to be of the same magnitude as in bulk silicon. Later research has shown the existence of such an effect where the film thickness has to be less than around 20 nm. 

    The second area that has been studied is the pressure sensitivity of in acoustic resonators. Aluminium nitride thin film plate acoustic resonators (FPAR) operating at the lowest-order symmetric (S0), the first-order asymmetric (A1) as well as the first-order symmetric (S1) Lamb modes have been theoretically and experimentally studied in a comparative manner. The S0 Lamb mode is identified as the most pressure sensitive FPAR mode. The theoretical predictions were found to be in good agreement with the experiments. Additionally, the Lamb modes have been tested for their sensitivities to mass loading and their ability to operate in liquids, where the S0 mode showed good results.

    Finally, the pressure sensitivity in aluminium nitride thin film bulk wave resonators employing c- and tilted c-axis texture has been studied. The c-axis tilted FBAR demonstrates a substantially higher pressure sensitivity compared to its c-axis oriented counterpart. 

    Delarbeten
    1. Resistance Electric Field Dependence and Time Drift of Piezoresistive Single Crystalline Silicon Nanofilms
    Öppna denna publikation i ny flik eller fönster >>Resistance Electric Field Dependence and Time Drift of Piezoresistive Single Crystalline Silicon Nanofilms
    2009 (Engelska)Ingår i: Proceedings of Eurosensors May 2009, Procedia Chemistry vol 1 (1), 2009, s. 80-83Konferensbidrag, Publicerat paper (Refereegranskat)
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:uu:diva-122014 (URN)
    Konferens
    Eurosensors May 2009, Proceedings of Eurosensors May 2009, Procedia Chemistry vol 1 (1)
    Projekt
    WISENETVR-621-2006-5881
    Tillgänglig från: 2010-04-06 Skapad: 2010-04-06 Senast uppdaterad: 2016-04-14Bibliografiskt granskad
    2. Drift in thin film SOI piezoresistors
    Öppna denna publikation i ny flik eller fönster >>Drift in thin film SOI piezoresistors
    Visa övriga...
    2010 (Engelska)Ingår i: Proc. of EUROSOI Workshop, 2010 Jan 25-27, Grenoble, France, 2010, s. 71-72Konferensbidrag, Enbart muntlig presentation (Refereegranskat)
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:uu:diva-136179 (URN)
    Konferens
    EUROSOI 2010 Jan 25-27, Grenoble, France
    Tillgänglig från: 2010-12-10 Skapad: 2010-12-10 Senast uppdaterad: 2016-04-18Bibliografiskt granskad
    3. Sensitivity Features of Thin Film Plate Acoustic Wave Resonators
    Öppna denna publikation i ny flik eller fönster >>Sensitivity Features of Thin Film Plate Acoustic Wave Resonators
    2011 (Engelska)Ingår i: IEEE Sensors Journal, ISSN 1530-437X, E-ISSN 1558-1748, Vol. 11, nr 12, s. 3330-3331Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Thin film plate acoustic resonators devices operating in the lowest order symmetric Lamb wave mode (S0) in coriented aluminum nitride (AlN) membranes on Si were fabricated and tested for their sensitivities to pressure and mass as well as for their ability to work in liquid environment.

    Ort, förlag, år, upplaga, sidor
    IEEE Sensors Council, 2011
    Nyckelord
    Film bulk acoustic resonators, Resonant frequency, Sensitivity, Sensors, Surface acoustic waves
    Nationell ämneskategori
    Annan elektroteknik och elektronik
    Forskningsämne
    Teknisk fysik med inriktning mot mikrosystemteknik; Teknisk fysik med inriktning mot elektronik
    Identifikatorer
    urn:nbn:se:uu:diva-157877 (URN)10.1109/JSEN.2011.2158094 (DOI)000301878500019 ()
    Projekt
    VR "Thin Film Guided Microacoustic Waves in Periodical Systems: Theory and Applications"
    Forskningsfinansiär
    Vetenskapsrådet, 2009-5056
    Tillgänglig från: 2011-08-24 Skapad: 2011-08-24 Senast uppdaterad: 2017-12-08Bibliografiskt granskad
    4. Lamb wave resonant pressure micro-sensor utilizing a thin-film aluminium nitride membrane
    Öppna denna publikation i ny flik eller fönster >>Lamb wave resonant pressure micro-sensor utilizing a thin-film aluminium nitride membrane
    2011 (Engelska)Ingår i: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 21, nr 8, s. 085010-Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    In this work, pressure sensitivities of aluminium nitride (AlN) thin film plate acoustic resonators (FPAR) operating at the lowest-order symmetric (S0), the first-order asymmetric (A1) as well as the first-order symmetric (S1) Lamb modes are theoretically and experimentally studied in a comparative manner. The finite element method analysis has also been performed to get a further insight into the FPAR pressure sensitivity. The theoretical predictions are found to be in good agreement with the experiment. The S0 Lamb mode is identified as the most pressure-sensitive FPAR mode, while the A1 and S1 modes are found to be much less sensitive. Further, the S0 and the A1 modes exhibit almost equal temperature sensitivities, which can be exploited to eliminate the temperature drift by comparing the resonance frequencies of the latter two modes.

    Nationell ämneskategori
    Teknik och teknologier
    Forskningsämne
    Teknisk fysik med inriktning mot elektronik
    Identifikatorer
    urn:nbn:se:uu:diva-157028 (URN)10.1088/0960-1317/21/8/085010 (DOI)000293163700010 ()
    Forskningsfinansiär
    Vetenskapsrådet, 2009-5056
    Tillgänglig från: 2011-08-16 Skapad: 2011-08-15 Senast uppdaterad: 2017-12-08
    5. Thin Film Plate Wave Resonant Sensor for Pressure and Gravimetric Measurements
    Öppna denna publikation i ny flik eller fönster >>Thin Film Plate Wave Resonant Sensor for Pressure and Gravimetric Measurements
    2011 (Engelska)Ingår i: Procedia Engineering 25, Eurosensors XXV: Proc. Eurosensors XXV, September 4-7, 2011, Athens, Greece, Elsevier, 2011, s. 571-574Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    Thin film plate acoustic resonators (FPAR) devices operating in the lowest order symmetric Lamb wave mode (S0),the first order asymmetric Lamb wave mode (A1) and the first order symmetric Lamb wave mode (S1), propagatingin c-oriented aluminum nitride (AlN) membranes on Si were fabricated and tested for their sensitivities to pressureand mass. Systematic data on frequency shifts versus rigid mass (layer) thickness and ambient pressure variations arepresented for the different Lamb wave resonances. Further the ability to work in liquid environment of the S0, A1 andS1 modes, respectively, has been tested in view of Bio-sensor applications.

    Ort, förlag, år, upplaga, sidor
    Elsevier, 2011
    Serie
    Procedia Engineering, ISSN 1877-7058 ; 25
    Nyckelord
    Micro, prssure, sensor, radio frequency
    Nationell ämneskategori
    Annan elektroteknik och elektronik
    Forskningsämne
    Teknisk fysik med inriktning mot mikrosystemteknik; Teknisk fysik med inriktning mot elektronik
    Identifikatorer
    urn:nbn:se:uu:diva-167002 (URN)10.1016/j.proeng.2011.12.142 (DOI)000300512400139 ()
    Konferens
    25th Eurosensors Conference, SEP 04-07, 2011, Athens, GREECE
    Projekt
    VR Granted
    Forskningsfinansiär
    Vetenskapsrådet, 2009-5056
    Tillgänglig från: 2012-01-18 Skapad: 2012-01-18 Senast uppdaterad: 2013-03-13
    6. Tilted c-Axis Thin-Film Bulk Wave Resonant Pressure Sensors With Improved Sensitivity
    Öppna denna publikation i ny flik eller fönster >>Tilted c-Axis Thin-Film Bulk Wave Resonant Pressure Sensors With Improved Sensitivity
    2012 (Engelska)Ingår i: IEEE Sensors Journal, ISSN 1530-437X, E-ISSN 1558-1748, Vol. 12, nr 8, s. 2653-2654Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Aluminum nitride thin film bulk wave resonant pressure sensors employing c- and tilted c-axis texture, have been fabricated and tested for their pressure sensitivities. The c-axis tilted FBAR pressure sensors demonstrate substantially higher pressure sensitivity compared to its c-axis oriented counterpart. More specifically the thickness plate quasi-shear resonance has demonstrated the highest pressure sensitivity while further being able to preserve its performance in liquid environment.

    Nyckelord
    AlN, FBAR, pressure sensor, sensitivity, micro-acoustic
    Nationell ämneskategori
    Annan elektroteknik och elektronik
    Forskningsämne
    Teknisk fysik med inriktning mot elektronik
    Identifikatorer
    urn:nbn:se:uu:diva-173179 (URN)10.1109/JSEN.2012.2199482 (DOI)000305584300003 ()
    Tillgänglig från: 2012-04-20 Skapad: 2012-04-20 Senast uppdaterad: 2017-12-07Bibliografiskt granskad
  • 14.
    Anderås, Emil
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Arapan, Lilia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Katardjiev, Ilia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Yantchev, Ventsislav
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Thin Film Plate Wave Resonant Sensor for Pressure and Gravimetric Measurements2011Ingår i: Procedia Engineering 25, Eurosensors XXV: Proc. Eurosensors XXV, September 4-7, 2011, Athens, Greece, Elsevier, 2011, s. 571-574Konferensbidrag (Refereegranskat)
    Abstract [en]

    Thin film plate acoustic resonators (FPAR) devices operating in the lowest order symmetric Lamb wave mode (S0),the first order asymmetric Lamb wave mode (A1) and the first order symmetric Lamb wave mode (S1), propagatingin c-oriented aluminum nitride (AlN) membranes on Si were fabricated and tested for their sensitivities to pressureand mass. Systematic data on frequency shifts versus rigid mass (layer) thickness and ambient pressure variations arepresented for the different Lamb wave resonances. Further the ability to work in liquid environment of the S0, A1 andS1 modes, respectively, has been tested in view of Bio-sensor applications.

  • 15.
    Anderås, Emil
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Katardjiev, Ilia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Yantchev, Ventsislav
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Tilted c-Axis Thin-Film Bulk Wave Resonant Pressure Sensors With Improved Sensitivity2012Ingår i: IEEE Sensors Journal, ISSN 1530-437X, E-ISSN 1558-1748, Vol. 12, nr 8, s. 2653-2654Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Aluminum nitride thin film bulk wave resonant pressure sensors employing c- and tilted c-axis texture, have been fabricated and tested for their pressure sensitivities. The c-axis tilted FBAR pressure sensors demonstrate substantially higher pressure sensitivity compared to its c-axis oriented counterpart. More specifically the thickness plate quasi-shear resonance has demonstrated the highest pressure sensitivity while further being able to preserve its performance in liquid environment.

  • 16.
    Andreasson, Joel
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Design och konstruktion av distorsionseffekt för gitarrer2019Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    This project has been done as a part of a bachelors degree in engineering at Uppsala university. The project was supervised by Jörgen Olsson at the division of solid state electronics.

    The goal of this project was to develop a distortion effect that can be used with an guitar and a amplifier. The effect was to have controllable distorsion, volume and tone control including bass and treble. The circuit is also supposed to be run using a 9V battery as power supply, which means that the in circuit currents shold be low. When the circuit was finished it was also analyzed through different measurements and simulations.

    The distortion of the circuit was achieved using diodes to get a nonlinear amplification. The goals of the circuit controls was achieved, and although a low circuit current was achieved, it only satisfied the goal of 1 mA when high distorsion was set for the circuit.

    When measuring and simulating the system, some major differences was found. The simulated frequency response characteristics was found to be very different from the measured. This is likely due to the simulation program not being

  • 17.
    Andreou, Charalambos M.
    et al.
    Univ Cyprus, Dept Elect & Comp Engn, CY-1678 Nicosia, Cyprus.
    Miguel Gonzalez-Castano, Diego
    Univ Santiago de Compostela, Radiat Phys Lab, E-15705 Santiago De Compostela, Spain.
    Gerardin, Simone
    Univ Padua, Dept Informat Engn, I-35122 Padua, Italy.
    Bagatin, Marta
    Univ Padua, Dept Informat Engn, I-35122 Padua, Italy.
    Gomez Rodriguez, Faustino
    Univ Santiago de Compostela, Radiat Phys Lab, E-15705 Santiago De Compostela, Spain.
    Paccagnella, Alessandro
    Univ Padua, Dept Informat Engn, I-35122 Padua, Italy.
    Prokofiev, Alexander
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Tillämpad kärnfysik.
    Javanainen, Arto
    Univ Jyvaskyla, Dept Phys, FI-40014 Jyvaskyla, Finland;Vanderbilt Univ, Dept Elect Engn & Comp Sci, Nashville, TN 37235 USA.
    Virtanen, Ari
    Univ Jyvaskyla, Dept Phys, FI-40014 Jyvaskyla, Finland.
    Liberali, Valentino
    Univ Milan, Dept Phys, I-20133 Milan, Italy.
    Calligaro, Cristiano
    RedCat Devices, I-20142 Milan, Italy.
    Nahmad, Daniel
    R&D Dept, Tower Semicond, IL-2310502 Migdal Haemeq, Israel.
    Georgiou, Julius
    Univ Cyprus, Dept Elect & Comp Engn, CY-1678 Nicosia, Cyprus.
    Low-Power, Subthreshold Reference Circuits for the Space Environment: Evaluated with -rays, X-rays, Protons and Heavy Ions2019Ingår i: ELECTRONICS, ISSN 2079-9292, Vol. 8, nr 5, artikel-id 562Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The radiation tolerance of subthreshold reference circuits for space microelectronics is presented. The assessment is supported by measured results of total ionization dose and single event transient radiation-induced effects under -rays, X-rays, protons and heavy ions (silicon, krypton and xenon). A high total irradiation dose with different radiation sources was used to evaluate the proposed topologies for a wide range of applications operating in harsh environments similar to the space environment. The proposed custom designed integrated circuits (IC) circuits utilize only CMOS transistors, operating in the subthreshold regime, and poly-silicon resistors without using any external components such as compensation capacitors. The circuits are radiation hardened by design (RHBD) and they were fabricated using TowerJazz Semiconductor's 0.18 m standard CMOS technology. The proposed voltage references are shown to be suitable for high-precision and low-power space applications. It is demonstrated that radiation hardened microelectronics operating in subthreshold regime are promising candidates for significantly reducing the size and cost of space missions due to reduced energy requirements.

  • 18.
    Ankarcrona, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    High Frequency Analysis of Silicon RF MOS Transistors2005Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Today, the silicon technology is well established for RF-applications (f~1-100 GHz), with emphasis on the lower frequencies (f < 5 GHz). The field of RF power devices is extensive concerning materials and devices. One of the important RF-devices is the silicon LDMOS transistor. A large extent of the research presented in the thesis concerns studies of this device, which have resulted in increased understanding of the device behavior and improved performance. The thesis starts with a brief survey of the RF-field, including the LDMOS transistor, followed by a description of the methods used in the investigations; simulations, modeling and measurements. Specific results presented in the appended papers are also briefly summarized.

    A new concept for LDMOS transistors, which allows for both high frequency and high voltage operation, has been developed and characterized. World-record performance in terms of output power density was obtained: over 1 W/mm at 50 V and 3.2 GHz. Further understanding and improvements of the device are achieved using simulations and modeling. For determination of model parameters a new general parameter extraction technique was developed. The method has been successfully used for a large variety of high-frequency devices, and has been frequently used in the modeling work in this thesis.

    Important properties of RF-power devices are the device linearity and power efficiency. Extensive studies regarding the efficiency were conducted using numerical simulations and modeling of the off-state output resistance, which is correlated to the efficiency. The results show that significant improvements can be obtained for devices on both bulk- and SOI-substrates, using thin high-resistivity substrates and very low-resistivity SOI-substrates, respectively.

    Finally a new approach to drastically reduce substrate crosstalk by using very low-resistivity SOI substrate is proposed. Experimentally, a reduction of 20-40 dB was demonstrated in the GHz range compared to high-resistivity SOI substrate.

    Delarbeten
    1. Sub-Circuit Based SPICE Model for High Voltage LDMOS Transistors
    Öppna denna publikation i ny flik eller fönster >>Sub-Circuit Based SPICE Model for High Voltage LDMOS Transistors
    2002 (Engelska)Ingår i: Physica Scripta, nr T101, s. 7-9Artikel i tidskrift (Refereegranskat) Published
    Nationell ämneskategori
    Annan elektroteknik och elektronik
    Forskningsämne
    Teknisk fysik med inriktning mot elektronik
    Identifikatorer
    urn:nbn:se:uu:diva-93398 (URN)
    Tillgänglig från: 2005-09-02 Skapad: 2005-09-02 Senast uppdaterad: 2012-09-26
    2. A General Small-Signal Series Impedance Extraction Technique
    Öppna denna publikation i ny flik eller fönster >>A General Small-Signal Series Impedance Extraction Technique
    2002 (Engelska)Ingår i: IEEE Microwave and Wireless Components Letters, ISSN 1531-1309, E-ISSN 1558-1764, Vol. 12, nr 7, s. 249-251Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    A new technique for extracting the series inductances and resistances in a small-signal equivalent circuit is presented. The technique does not rely on approximation and should therefore be as accurate as the measured data. The technique can also be used to extract the intrinsic parameters if they are not easily achieved using other methods. The method is exemplified with a microwave LDMOS transistor

    Nyckelord
    S-parameters, microwave LDMOS transistor, parameter estimation, series inductances, series resistances, small-signal equivalent circuit, small-signal series impedance extraction technique
    Nationell ämneskategori
    Annan elektroteknik och elektronik
    Identifikatorer
    urn:nbn:se:uu:diva-93400 (URN)10.1109/LMWC.2002.801134 (DOI)
    Tillgänglig från: 2005-09-02 Skapad: 2005-09-02 Senast uppdaterad: 2017-12-14Bibliografiskt granskad
    3. Analysis and Design of a Low-Voltage High-Frequency LDMOS Transistor
    Öppna denna publikation i ny flik eller fönster >>Analysis and Design of a Low-Voltage High-Frequency LDMOS Transistor
    2002 (Engelska)Ingår i: IEEE Transactions on Electron Devices, ISSN 0018-9383, E-ISSN 1557-9646, Vol. 49, nr 6, s. 976-980Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    For a low voltage lateral double-diffused MOS (LDMOS) transistor, the output performance has been improved in terms of fMAX. This is done by decreasing the output capacitance and thus decreasing the total output conductance. Extraction of the model parameters has been made and the most efficient parameter to improve was identified and linked to a specific part of the transistor structure. Layout changes in the n-well/p-base region were done as the result of the model analyses and finally, the modified devices were processed. Measurements on the improved devices showed results that closely, matched the expected, and fMAX was increased with 30% and only a slight decrease in f T. Finally, the capacitance reduction in the n-well/p-base junction was measured by direct. measurements

    Nyckelord
    LV HF LDMOS transistor, S-parameter, current-voltage characteristics, equivalent circuits, layout changes, microwave FET, model parameters, n-well/p-base junction, output capacitance, output performance, small-signal parameters, total output conductance
    Nationell ämneskategori
    Annan elektroteknik och elektronik
    Identifikatorer
    urn:nbn:se:uu:diva-93401 (URN)10.1109/TED.2002.1003715 (DOI)
    Tillgänglig från: 2005-09-02 Skapad: 2005-09-02 Senast uppdaterad: 2017-12-14
    4. Simulation and modeling of the substrate contribution to the output resistance for RF-LDMOS power transistors
    Öppna denna publikation i ny flik eller fönster >>Simulation and modeling of the substrate contribution to the output resistance for RF-LDMOS power transistors
    2004 (Engelska)Ingår i: Solid-State Electronics, ISSN 0038-1101, E-ISSN 1879-2405, Vol. 48, nr 5, s. 789-797Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    High frequency substrate losses for RF MOSFETs are analyzed using numerical device simulation. The results show that losses in devices made on low resistivity substrate occur through the substrate while losses in devices made on high resistivity substrate in the high frequency region occur along the surface through the device (source–drain). An equivalent circuit model is developed which accurately describes the off-state losses. Based on the model significant improvements in terms of output resistance are demonstrated, using an improved device on high resistivity substrate.

    Nyckelord
    Substrate losses, Modeling, RF MOSFET, LDMOS
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:uu:diva-93402 (URN)10.1016/j.sse.2003.12.005 (DOI)
    Tillgänglig från: 2005-09-02 Skapad: 2005-09-02 Senast uppdaterad: 2017-12-14
    5. Improved Output Resistance in RF-power MOSFETs using Low Resistivity SOI Substrate
    Öppna denna publikation i ny flik eller fönster >>Improved Output Resistance in RF-power MOSFETs using Low Resistivity SOI Substrate
    Visa övriga...
    (Engelska)Manuskript (Övrigt vetenskapligt)
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:uu:diva-93403 (URN)
    Tillgänglig från: 2005-09-02 Skapad: 2005-09-02 Senast uppdaterad: 2015-07-21Bibliografiskt granskad
    6. Low Resistivity SOI for Substrate Crosstalk Reduction
    Öppna denna publikation i ny flik eller fönster >>Low Resistivity SOI for Substrate Crosstalk Reduction
    2005 (Engelska)Ingår i: IEEE Transactions on Electron Devices, ISSN 0018-9383, E-ISSN 1557-9646, IEEE Trans on Electronic Devices, Vol. 52, nr 8, s. 1920-1922Artikel i tidskrift (Refereegranskat) Published
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:uu:diva-93404 (URN)
    Tillgänglig från: 2005-09-02 Skapad: 2005-09-02 Senast uppdaterad: 2017-12-14Bibliografiskt granskad
    7. 1 W/mm RF Power Denisty at 3.2 GHz for a Dual-Layer RESURF LDMOS Transistor
    Öppna denna publikation i ny flik eller fönster >>1 W/mm RF Power Denisty at 3.2 GHz for a Dual-Layer RESURF LDMOS Transistor
    Visa övriga...
    2002 (Engelska)Ingår i: IEEE Electron Device Letters, ISSN 0741-3106, Vol. 23, nr 4, s. 206-208Artikel i tidskrift (Refereegranskat) Published
    Nationell ämneskategori
    Annan elektroteknik och elektronik
    Identifikatorer
    urn:nbn:se:uu:diva-41678 (URN)10.1109/55.992840 (DOI)
    Tillgänglig från: 2007-02-23 Skapad: 2007-02-23 Senast uppdaterad: 2010-07-09Bibliografiskt granskad
  • 19.
    Ankarcrona, Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Eklund, Klas-Håkan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Vestling, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Olsson, Jörgen
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Analysis and improvments of high frequency substrate losses for RF MOSFETs2003Ingår i: Proceedings of IEEE SISPAD, 2003, s. 319-322Konferensbidrag (Refereegranskat)
  • 20.
    Ankarcrona, Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Eklund, Klas-Håkan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Vestling, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Olsson, Jörgen
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Simulation and modeling of the substrate influence on the high frequency performance for RF LDMOS2003Ingår i: GHz2003 Symposium, Nov. 4-5, 2003Konferensbidrag (Refereegranskat)
  • 21.
    Ankarcrona, Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för materialvetenskap. Institutionen för teknikvetenskaper, Elektronik. Fasta tillståndets elektronik.
    Olsson, Jörgen
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för materialvetenskap. Institutionen för teknikvetenskaper, Elektronik. Fasta tillståndets elektronik.
    SPICE Modeling of High Voltage LDMOS Transistors2001Ingår i: The 19th Nordic Semiconductor Meeting, Copenhagen, Denmark, May, 2001Konferensbidrag (Refereegranskat)
  • 22.
    Ankarcrona, Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Olsson, Jörgen
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Sub-Circuit Based SPICE Model for High Voltage LDMOS Transistors2002Ingår i: Physica Scripta, nr T101, s. 7-9Artikel i tidskrift (Refereegranskat)
  • 23. Anthon, Jonsson
    et al.
    Vincent, Ricknell
    Project in Electrical Engineering: Electric Skateboard2017Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
  • 24.
    Apelfröjd, Senad
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Bülow, Fredrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Kjellin, Jon
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Eriksson, Sandra
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Laboratory verification of system for grid connection of a 12 kW variable speed wind turbine with a permanent magnet synchronous generator2012Ingår i: EWEA 2012 Annual Event, Copenhagen, Denmark, 2012, 2012Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper the first laboratory tests of the gridconnection system, connected to a resistiveload, for a vertical axis wind turbine (VAWT)with a permanent magnet generator arepresented. The system is based on a taptransformertopology with a voltage sourceinverter and an LCL-filter. The use of a taptransformer topology eliminates the need for aDC-DC converter to handle the variations inDC voltage. The harmonic content of thecurrents from experiments and simulationsperformed in Simulink using different taps onthe transformer are presented. The simulatedcurrents, fed to the resistive load, have a totalharmonic distortion (THD) of 0.5% to 0.9% forthe different taps. The experimental systemhas a current THD ranging from 1.8% to 2.8%.The difference is expected to be due tounbalances, delays and dead times in theexperimental set-up as the major THDcontribution is from harmonic orders below 11.The results show that an LCL filter can bedesigned to meet the demands on powerquality for grid connection of the system withall the taps of the tap transformer inaccordance with IEEE 519-1992.

  • 25.
    Arapan, Lilia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Thin Film Plate Acoustic Resonators for Frequency Control and Sensing Applications2012Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The recent development of the commercially viable thin film electro-acoustic technology has triggered a growing interest in the research of plate guided wave or Lamb wave components owing to their unique characteristics. In the present thesis i) an experimental study of the thin film plate resonators (FPAR) performance operating on the lowest symmetrical Lamb wave (S0) propagating in highly textured AlN membranes versus a variety of design parameters has been performed. The S0 mode is excited through an Interdigital Transducer and confined within the structure by means of reflection from metal strip gratings. Devices operating in the vicinity of the stop-band center exhibiting a Q-value of up to 3000 at a frequency around 900MHz have been demonstrated. Temperature compensation of this type of devices has been studied theoretically and successfully realized experimentally for the first time. Further, integrated circuit-compatible S0 Lamb based two-port FPAR stabilized oscillators exhibiting phase noise of -92 dBc/Hz at 1 kHz frequency offset with feasible thermal noise floor below -180 dBc/Hz have been tested under high power for a couple of weeks. More specifically, the FPARs under test have been running without any performance degradation at up to 27 dBm loop power. Further, the S0 mode was experimentally demonstrated to be highly mass and pressure sensitive as well as suitable for in-liquid operation, which together with low phase noise and high Q makes it very suitable for sensor applications; ii) research in view of FPARs operating on other types of Lamb waves as well as novel operation principles has been initiated. In this work, first results on the design, fabrication and characterization of two novel type resonators: The Zero Group Velocity Resonators (ZGVR) and The Intermode-Coupled Thin Film Plate Acoustic Resonators (IC-FPAR), exploiting new principles of operation have been successfully demonstrated. The former exploits the intrinsic zero group velocity feature of the S1 Lamb mode for certain combination of design parameters while the latter takes advantage of the intermode interaction (involving scattering) between S0 and A1 Lamb modes through specially designed metal strip gratings (couplers). Thus both type of resonators operate on principles of confining energy under IDT other than reflection.

    Delarbeten
    1. Micromachined Thin Film Plate Acoustic Wave Resonators (FPAR) Part II
    Öppna denna publikation i ny flik eller fönster >>Micromachined Thin Film Plate Acoustic Wave Resonators (FPAR) Part II
    2009 (Engelska)Ingår i: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, ISSN 0885-3010, E-ISSN 1525-8955, Vol. 56, nr 12, s. 2701-2710Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Improved performance thin-film plate acousticwave resonators (FPAR) using the lowest order symmetricLamb wave (S0) propagating in highly textured AlN membraneshave been previously demonstrated for the first time.In this work, an experimental study of the resonators’ performancevs. a variety of design parameters is performed. Devicesoperating in the vicinity of the stopband center exhibiting aQ-value of up to 3000 at a frequency of around 875 MHz aredemonstrated. Further, low-loss high-Q micromachined 2-portlongitudinally coupled thin-film resonators using the S0 modeare demonstrated for the first time. For the analysis of theproposed structures, the coupling-of-modes (COM) approachis successfully employed. Initially, the COM model is used forthe extraction of physical parameters from one-port FPARmeasurements. Subsequently, using the COM model, a satisfactoryagreement with the proposed experimental frequencycharacteristics of S0 2-port FPARs has been achieved, andpossibilities for further improvements in the performance discussed.Finally, the frequency spectrum of the one-port deviceshas been studied and the excited plate modes at differentfrequencies identified and presented with their Q-factors andtemperature coefficients of frequency (TCF).

    Nyckelord
    Thin films, Resonator, Micromachining, MEMS, NEMS
    Nationell ämneskategori
    Elektroteknik och elektronik
    Forskningsämne
    Teknisk fysik med inriktning mot mikrosystemteknik
    Identifikatorer
    urn:nbn:se:uu:diva-111379 (URN)10.1109/TUFFC.2009.1361 (DOI)000272593100011 ()
    Projekt
    VR Funded "Thin Film Guided Microacoustic Waves in Periodical Structures: Theory and Applications"
    Forskningsfinansiär
    Vetenskapsrådet, 2009-5056
    Tillgänglig från: 2009-12-12 Skapad: 2009-12-12 Senast uppdaterad: 2017-12-12
    2. Micromachined thermally compensated thin film Lamb wave resonator for frequency control and sensing applications
    Öppna denna publikation i ny flik eller fönster >>Micromachined thermally compensated thin film Lamb wave resonator for frequency control and sensing applications
    2009 (Engelska)Ingår i: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 19, nr 3, s. 035018-Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Micromachined thin film plate acoustic wave resonators (FPAR) utilizing the lowest order symmetric Lamb wave (S0) propagating in highly textured 2μm thick Aluminum Nitride (AlN) membranes have been successfully demonstrated [1]. The proposed devices have a SAW-based design and exhibit Q factors of up to 3000 at a frequency around 900MHz as well as design flexibility with respect to the required motional resistance. However, a notable drawback of the proposed devices is non-zero temperature coefficient of frequency (TCF) which lies in the range -20 ppm/K to –25 ppm/K. Thus, despite the promising features demonstrated, further device optimization is required. In this work temperature compensation of thin AlN film Lamb wave resonators is studied and experimentally demonstrated. Temperature compensation while retaining at the same time the device electromechanical coupling is experimentally demonstrated. The zero TCF Lamb wave resonators are fabricated onto composite AlN/SiO2 membranes. Q factors of around 1400 have been measured at a frequency of around 755 MHz. Finally, the impact of technological issues on the device performance is discussed in view of improving the device performance.

    Nationell ämneskategori
    Annan elektroteknik och elektronik
    Forskningsämne
    Elektronik
    Identifikatorer
    urn:nbn:se:uu:diva-89404 (URN)10.1088/0960-1317/19/3/035018 (DOI)000263678200019 ()
    Projekt
    WISENET
    Forskningsfinansiär
    Vetenskapsrådet, 2009-5056
    Tillgänglig från: 2009-02-12 Skapad: 2009-02-12 Senast uppdaterad: 2018-06-26Bibliografiskt granskad
    3. Thin film plate acoustic resonators for integrated microwave power oscillator applications
    Öppna denna publikation i ny flik eller fönster >>Thin film plate acoustic resonators for integrated microwave power oscillator applications
    2011 (Engelska)Ingår i: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 47, nr 7, s. 452-453Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Two-port film plate acoustic resonators (FPAR) devices operating on the lowest order symmetric Lamb wave mode (S0) in C-oriented AlN membranes on Si were fabricated and tested for their power handling capabilities in a feedback-loop power oscillator circuit. The FPAR was operated at an incident power level of 24 dBm for several weeks without performance degradation. Its flicker noise constant was calculated from close-in phase noise data as αR=2.1×10^−36/Hz. The results indicate that IC-compatible S0 FPARs are well suited for integrated microwave oscillators with thermal noise floor (TNF) levels below −175 dBc/Hz.

    Nyckelord
    Powe oscillator, low noise, MEMS, piezo
    Nationell ämneskategori
    Annan elektroteknik och elektronik
    Forskningsämne
    Teknisk fysik med inriktning mot mikrosystemteknik; Teknisk fysik med inriktning mot elektronik
    Identifikatorer
    urn:nbn:se:uu:diva-150468 (URN)10.1049/el.2011.0381 (DOI)000288893100023 ()
    Projekt
    VR "Thin Film Guided Microacoustic Waves in Periodical Systems: Theory and Applications"
    Forskningsfinansiär
    Vetenskapsrådet, 2009-5056
    Tillgänglig från: 2011-03-30 Skapad: 2011-03-30 Senast uppdaterad: 2017-12-11Bibliografiskt granskad
    4. Sensitivity Features of Thin Film Plate Acoustic Wave Resonators
    Öppna denna publikation i ny flik eller fönster >>Sensitivity Features of Thin Film Plate Acoustic Wave Resonators
    2011 (Engelska)Ingår i: IEEE Sensors Journal, ISSN 1530-437X, E-ISSN 1558-1748, Vol. 11, nr 12, s. 3330-3331Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Thin film plate acoustic resonators devices operating in the lowest order symmetric Lamb wave mode (S0) in coriented aluminum nitride (AlN) membranes on Si were fabricated and tested for their sensitivities to pressure and mass as well as for their ability to work in liquid environment.

    Ort, förlag, år, upplaga, sidor
    IEEE Sensors Council, 2011
    Nyckelord
    Film bulk acoustic resonators, Resonant frequency, Sensitivity, Sensors, Surface acoustic waves
    Nationell ämneskategori
    Annan elektroteknik och elektronik
    Forskningsämne
    Teknisk fysik med inriktning mot mikrosystemteknik; Teknisk fysik med inriktning mot elektronik
    Identifikatorer
    urn:nbn:se:uu:diva-157877 (URN)10.1109/JSEN.2011.2158094 (DOI)000301878500019 ()
    Projekt
    VR "Thin Film Guided Microacoustic Waves in Periodical Systems: Theory and Applications"
    Forskningsfinansiär
    Vetenskapsrådet, 2009-5056
    Tillgänglig från: 2011-08-24 Skapad: 2011-08-24 Senast uppdaterad: 2017-12-08Bibliografiskt granskad
    5. Highly Mass-Sensitive Thin Film Plate Acoustic Resonators (FPAR)
    Öppna denna publikation i ny flik eller fönster >>Highly Mass-Sensitive Thin Film Plate Acoustic Resonators (FPAR)
    Visa övriga...
    2011 (Engelska)Ingår i: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 11, nr 7, s. 6942-6953Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    The mass sensitivity of thin aluminum nitride (AlN) film S0 Lamb wave resonators is theoretically and experimentally studied. Theoretical predictions based on modal and finite elements method analysis are experimentally verified. Here, two-port 888 MHz synchronous FPARs are micromachined and subsequently coated with hexamethyl-disiloxane(HMDSO)-plasma-polymerized thin films of various thicknesses. Systematic data on frequency shift and insertion loss versus film thickness are presented. FPARs demonstrate high mass-loading sensitivity as well as good tolerance towards the HMDSO viscous losses. Initial measurements in gas phase environment are further presented.

    Nyckelord
    resonator, aluminum nitride, membrane, HMDSO, gravimetric, sensitivity
    Nationell ämneskategori
    Teknik och teknologier
    Forskningsämne
    Teknisk fysik med inriktning mot mikrosystemteknik; Teknisk fysik med inriktning mot elektronik
    Identifikatorer
    urn:nbn:se:uu:diva-157836 (URN)10.3390/s110706942 (DOI)000293069200027 ()
    Projekt
    VR "Thin Film Guided Microacoustic Waves in Periodical Systems: Theory and Applications"
    Tillgänglig från: 2011-08-24 Skapad: 2011-08-23 Senast uppdaterad: 2017-12-08Bibliografiskt granskad
    6. Thin-film zero-group-velocity Lamb wave resonator
    Öppna denna publikation i ny flik eller fönster >>Thin-film zero-group-velocity Lamb wave resonator
    2011 (Engelska)Ingår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 99, nr 3, artikel-id 033505Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    A concept for the development of thin film micro-acoustic resonators is demonstrated. The basicprinciples for the design and fabrication of zero-group-velocity Lamb acoustic wave resonators onc-textured thin aluminum nitride films are presented. The experimental results demonstrate that thezero-group-velocity waves can be employed in high frequency resonators with small form factors.

    Nyckelord
    acoustic resonators, aluminium compounds, micromechanical resonators, surface acoustic waves
    Nationell ämneskategori
    Teknik och teknologier
    Forskningsämne
    Teknisk fysik med inriktning mot mikrosystemteknik; Teknisk fysik med inriktning mot elektronik
    Identifikatorer
    urn:nbn:se:uu:diva-157833 (URN)10.1063/1.3614559 (DOI)000293679000069 ()
    Projekt
    VR, "Thin Film Guided Microacoustic Waves in Periodical Systems: Theory and Applications"
    Forskningsfinansiär
    Vetenskapsrådet, 2009-5056
    Tillgänglig från: 2011-08-23 Skapad: 2011-08-23 Senast uppdaterad: 2017-12-08Bibliografiskt granskad
    7. An intermode-coupled thin-film micro-acoustic resonator
    Öppna denna publikation i ny flik eller fönster >>An intermode-coupled thin-film micro-acoustic resonator
    2012 (Engelska)Ingår i: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 22, nr 8, s. 085004-Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    A novel concept for the development of thin-film micro-acoustic resonators based on the coupling between different plate acoustic modes was demonstrated. The basic principles for the design and fabrication of intermode-coupled plate acoustic wave resonators on c-textured thin AlN films were presented and first experimental proof of coupling between laterally propagating waves and BAW was demonstrated. The experimental results demonstrate that the grating-assisted intermode coupling can be employed in high-frequency resonators inheriting the low dispersive nature of the S0 mode in combination with the energy localization in the plate bulk typical for the fundamental thickness shear resonance.

    Nyckelord
    acoustic resonator, aluminium nitride, Lamb wave, mode conversion
    Nationell ämneskategori
    Annan elektroteknik och elektronik
    Forskningsämne
    Teknisk fysik med inriktning mot elektronik; Teknisk fysik med inriktning mot mikrosystemteknik
    Identifikatorer
    urn:nbn:se:uu:diva-178590 (URN)10.1088/0960-1317/22/8/085004 (DOI)000306649000004 ()
    Forskningsfinansiär
    Vetenskapsrådet, 2009-5056
    Tillgänglig från: 2012-08-01 Skapad: 2012-08-01 Senast uppdaterad: 2017-12-07Bibliografiskt granskad
  • 26.
    Arapan, Lilia
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Anderås, Emil
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Katardjiev, Ilia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Yantchev, Ventsislav
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Sensitivity Features of Thin Film Plate Acoustic Wave Resonators2011Ingår i: IEEE Sensors Journal, ISSN 1530-437X, E-ISSN 1558-1748, Vol. 11, nr 12, s. 3330-3331Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Thin film plate acoustic resonators devices operating in the lowest order symmetric Lamb wave mode (S0) in coriented aluminum nitride (AlN) membranes on Si were fabricated and tested for their sensitivities to pressure and mass as well as for their ability to work in liquid environment.

  • 27.
    Arapan, Lilia
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Avramov, Ivan
    Inst Solid State Physics, Bulgarian Academy of Sciences.
    Yantchev, Ventsislav
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Thin film plate acoustic resonators for integrated microwave power oscillator applications2011Ingår i: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 47, nr 7, s. 452-453Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Two-port film plate acoustic resonators (FPAR) devices operating on the lowest order symmetric Lamb wave mode (S0) in C-oriented AlN membranes on Si were fabricated and tested for their power handling capabilities in a feedback-loop power oscillator circuit. The FPAR was operated at an incident power level of 24 dBm for several weeks without performance degradation. Its flicker noise constant was calculated from close-in phase noise data as αR=2.1×10^−36/Hz. The results indicate that IC-compatible S0 FPARs are well suited for integrated microwave oscillators with thermal noise floor (TNF) levels below −175 dBc/Hz.

  • 28.
    Arapan, Lilia
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Katardjiev, Ilia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Yantchev, Ventsislav
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    An intermode-coupled thin-film micro-acoustic resonator2012Ingår i: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 22, nr 8, s. 085004-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A novel concept for the development of thin-film micro-acoustic resonators based on the coupling between different plate acoustic modes was demonstrated. The basic principles for the design and fabrication of intermode-coupled plate acoustic wave resonators on c-textured thin AlN films were presented and first experimental proof of coupling between laterally propagating waves and BAW was demonstrated. The experimental results demonstrate that the grating-assisted intermode coupling can be employed in high-frequency resonators inheriting the low dispersive nature of the S0 mode in combination with the energy localization in the plate bulk typical for the fundamental thickness shear resonance.

  • 29.
    Arapan, Lilia
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Katardjiev, Ilia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Yantchev, Ventsislav
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Alexieva, Gergana
    Dept of Solid State Physics and Microelectronics, University of Sofia.
    Strashilov, Vesseline
    Dept of Solid State Physics and Microelectronics, University of Sofia.
    Avramov, Ivan
    Georgy Nadjakov Institute of Solid State Physics, Sofia, Bulgarian Academy of Sciences.
    Radeva, Ekaterina
    Georgy Nadjakov Institute of Solid State Physics, Sofia, Bulgarian Academy of Sciences.
    Polymer coated thin film plate acoustic resonators (FPAR) for gas sensing applications2011Ingår i: 2011 Joint Conference of the IEEE International Frequency Control Symposium and European Frequency and Time Forum Proceedings, San Fransisco, CA, USA, 2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    Mass sensitivity of thin aluminum nitride (AlN) film S0 plate wave resonators is theoretically and experimentally studied. Here, two-port 888MHz synchronous thin film plate acoustic resonators (FPAR) are micromachined and subsequently coated with plasma-polymerized hexamethyldisiloxane (pp-HMDSO) thin films of various thicknesses. Systematic data on frequency shift and insertion loss versus film thickness are presented in a comparative manner. Measurements in gas phase environment are further presented in a comparative manner.

  • 30.
    Arevalo, Liliana
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Numerical Simulations of Long Spark and Lightning Attachment2011Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The research work presented here is concerned with numerical simulations of two different electrical phenomena: Long gap electrical discharges under switching impulses and the lightning attachment process associated with positive upward leaders. The development of positive upward leaders and the progression of discharges in long gaps are attributable to two intertwined physical phenomena, namely, the leader channel and the streamer zone. The physical description and the proposed calculations of the above-mentioned phenomena are based on experimental tests conducted in long spark gaps.

    The methodology presented here proposes a new geometrical approximation for the representation of the streamer and the calculation of the accumulated electrical charge. Furthermore, two different approaches to representing the leader channel are applied and compared. Statistical delays before the inception of the first corona, and random distributions to represent the tortuous nature of the path taken by the leader channel were included based on the behavior observed in experimental tests, with the intention of ensuring the discharge behaved in a realistic manner. A reasonable agreement was found between the physical model and the experimental test results.

    A model is proposed to simulate the negative discharges produced by switching impulses using the methodology developed to simulate positive leader discharges and the physics underlying the negative leader phenomena. The validation of the method demonstrated that phenomena such as the pilot leader and negative leader currents are successfully represented.

    In addition, based on previous work conducted on the physics of lightning and the lightning attachment process, a new methodology is developed and tested. In this new approach, the background electric field and the ionized region, considered in conjunction with the advance of the leader segment, are computed using a novel method. The proposed methodology was employed to test two engineering methods that are accepted in international standards, the mesh method and the electro-geometrical method. The results demonstrated that the engineering approximations are consistent with the physical approach.

    In addition to the electrical phenomena mentioned above, one should remember that, to simplify the calculation, there are certain real effects arising from the lightning attachment process that have not been considered. In fact, when a structure is subjected to a strong electric field, it is possible to generate multiple upward leaders from that structure. This effect has not been taken into account in the numerical models available previously, and therefore the process of generating multiple upward leaders incepted over a structure is incorporated here. The results have shown that a slight advantage from the background electric field is enough for one upward connecting leader to take over, thereby forcing the others to abort the attachment process.

    Delarbeten
    1. Modelling of Positive Discharges in Laboratory Gaps under Switching impulses
    Öppna denna publikation i ny flik eller fönster >>Modelling of Positive Discharges in Laboratory Gaps under Switching impulses
    2008 (Engelska)Konferensbidrag, Publicerat paper (Refereegranskat)
    Ort, förlag, år, upplaga, sidor
    Cardiff, UK: , 2008
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:uu:diva-113403 (URN)
    Konferens
    XVII International Conference on Gas Discharges and Their applications
    Tillgänglig från: 2010-01-28 Skapad: 2010-01-28 Senast uppdaterad: 2016-04-12Bibliografiskt granskad
    2. Breakdown effect on long gaps under switching impulses statistical variation
    Öppna denna publikation i ny flik eller fönster >>Breakdown effect on long gaps under switching impulses statistical variation
    2008 (Engelska)Konferensbidrag, Publicerat paper (Refereegranskat)
    Ort, förlag, år, upplaga, sidor
    Uppsala, Sweden: , 2008
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:uu:diva-113402 (URN)
    Konferens
    29th International Conference on Lightning Protection
    Tillgänglig från: 2010-01-28 Skapad: 2010-01-28 Senast uppdaterad: 2016-04-12Bibliografiskt granskad
    3. Breakdown times and voltages probability calculation using a simplified numerical methodology
    Öppna denna publikation i ny flik eller fönster >>Breakdown times and voltages probability calculation using a simplified numerical methodology
    2008 (Engelska)Konferensbidrag, Publicerat paper (Refereegranskat)
    Ort, förlag, år, upplaga, sidor
    Florianopolis Brazil: , 2008
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:uu:diva-113401 (URN)
    Konferens
    International Conference on Grounding and Earthing and 3rd International Conference on Lightning Physics and Effects
    Tillgänglig från: 2010-01-28 Skapad: 2010-01-28 Senast uppdaterad: 2016-04-12Bibliografiskt granskad
    4. Numerical simulation of long laboratory sparks generated by positive switching impulses
    Öppna denna publikation i ny flik eller fönster >>Numerical simulation of long laboratory sparks generated by positive switching impulses
    2009 (Engelska)Ingår i: Journal of Electrostatics, ISSN 0304-3886, E-ISSN 1873-5738, Vol. 67, nr 2-3, s. 228-234Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    A numerical methodology using two different leader channel criteria has been implemented. The methodology is based on Bondiou and Gallimberti's proposition [A. Bondiou, I. Gallimberti, Theoretical modelling of the development of the positive spark in long spark, J. Phys. D: Appl. Phys. 27 (1994) 1252-1266]. The leader channel criteria used are Rizk engineering criterion [Rizk, A model for switching impulse leader inception and breakdown of long air gaps, IEEE Trans. Power Deliv., 4(1) (1989)] and Local thermodynamic - L.T.E. - physical concept [I. Gallimberti, The mechanism of the long spark formation, Colloque C7, J. Phys. (supplement au nro 7, Tome 40) (July 1979) C7-193]. The methodology was tested in three different cases; a deterministic case, a statistical variation and a typical constant level test. Deterministic calculation considered corona inception using stabilization corona electric field criterion of Gallimberti [I. Gallimberti, The mechanism of the long spark formation, Colloque C7, J. Phys. (supplement au nro 7, Tome 40) (July 1979) C7-193] and the leader moving as segments. The statistical simulation has two different statistical delays, one at inception and the other due to the tortuous characteristics of the leader channel. The constant level test consists of 200 positive switching impulses with the same characteristics such as maximum applied voltage, time to crest and time to fall. Time to breakdown and breakdown voltage were found based on the results obtained from the constant level test characteristics. All the numerical results presented are based on experimental conditions reported in [Les Renardières Group, Research on long gap discharges at Les Renardières, Electra N 35 (1973)] from the world class research group namely Les Renardieres Group.

    Nyckelord
    Discharge, Leader, Modeling, Switching
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:uu:diva-113133 (URN)10.1016/j.elstat.2008.12.022 (DOI)000266019500029 ()0304-3886 (ISBN)
    Tillgänglig från: 2010-01-25 Skapad: 2010-01-25 Senast uppdaterad: 2017-12-12Bibliografiskt granskad
    5. LABORATORY LONG GAPS SIMULATION CONSIDERING A VARIABLE CORONA REGION
    Öppna denna publikation i ny flik eller fönster >>LABORATORY LONG GAPS SIMULATION CONSIDERING A VARIABLE CORONA REGION
    2010 (Engelska)Konferensbidrag, Publicerat paper (Refereegranskat)
    Ort, förlag, år, upplaga, sidor
    Cagliary, Italy: , 2010
    Nationell ämneskategori
    Teknik och teknologier
    Forskningsämne
    Teknisk fysik med inriktning mot atmosfäriska urladdningar
    Identifikatorer
    urn:nbn:se:uu:diva-140390 (URN)
    Konferens
    30TH International Conference on Lightning Protection, ICLP
    Tillgänglig från: 2011-01-05 Skapad: 2011-01-05 Senast uppdaterad: 2016-03-03
    6. A RELIABLE NUMERICAL METHOD FOR THE CALCULATION OF BREAKDOWN VOLTAGES
    Öppna denna publikation i ny flik eller fönster >>A RELIABLE NUMERICAL METHOD FOR THE CALCULATION OF BREAKDOWN VOLTAGES
    2010 (Engelska)Konferensbidrag, Publicerat paper (Refereegranskat)
    Ort, förlag, år, upplaga, sidor
    Cagliary, Italy: , 2010
    Nationell ämneskategori
    Teknik och teknologier
    Forskningsämne
    Teknisk fysik med inriktning mot atmosfäriska urladdningar
    Identifikatorer
    urn:nbn:se:uu:diva-140391 (URN)
    Konferens
    30TH International Conference on Lightning Protection, ICLP
    Tillgänglig från: 2011-01-05 Skapad: 2011-01-05 Senast uppdaterad: 2014-12-10
    7. A new static calculation of the streamer region for long spark gaps
    Öppna denna publikation i ny flik eller fönster >>A new static calculation of the streamer region for long spark gaps
    2012 (Engelska)Ingår i: Journal of Electrostatics, ISSN 0304-3886, E-ISSN 1873-5738, Vol. 70, nr 1, s. 15-19Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Different electrostatic approximations have been proposed to calculate the streamer region without going in deep details of the behavior of density of particles under the effect of high electric fields; this kind of approximations have been used in numerical calculations of long spark gaps and lightning attachment. The simplifications of the streamer region are achieved by considering it to be a geometrical region with a constant geometrical shape. Different geometrical shapes have been used, such as cones or several parallel filaments. Afterward, to simplify the procedures, the streamer region was approximated by two constants, one denoted K-Q, called the geometrical constant and in other cases K named as geometrical factor. However, when a voltage that varies with time is applied to an arrangement of electrodes (high voltage and grounded electrodes), the background electric field will change with time. Thus, if the background electric field is modified, the streamer zone could cover a larger or smaller area. With the aim of reducing the number of assumptions required in the calculation of long gap discharges, a new electrostatic model to calculate the streamer region is presented. This model considers a variable streamer zone that changes with the electric field variations. The three-dimensional region that fulfills the minimum electric field to sustain a streamer is identified for each time step, and the charge accumulated in that region is then calculated. The only parameter that is being used in the calculation is the minimum electric field necessary for the propagation of streamers.

    Nyckelord
    charge, leader, Streamer, Electrical charge, Electric field, Corona inception, Discharge
    Nationell ämneskategori
    Elektroteknik och elektronik
    Forskningsämne
    Elektricitetslära, ssk studiet av transienter och urladdning; Teknisk fysik med inriktning mot elektricitetslära
    Identifikatorer
    urn:nbn:se:uu:diva-150528 (URN)10.1016/j.elstat.2011.07.013 (DOI)000300804300003 ()
    Tillgänglig från: 2011-03-31 Skapad: 2011-03-31 Senast uppdaterad: 2017-12-11Bibliografiskt granskad
    8. The development of long spark gaps: Simulation including a variable streamer region
    Öppna denna publikation i ny flik eller fönster >>The development of long spark gaps: Simulation including a variable streamer region
    (Engelska)Artikel i tidskrift (Refereegranskat) Submitted
    Nyckelord
    Breakdown, streamer, discharge
    Nationell ämneskategori
    Annan elektroteknik och elektronik
    Forskningsämne
    Teknisk fysik med inriktning mot atmosfäriska urladdningar
    Identifikatorer
    urn:nbn:se:uu:diva-150531 (URN)
    Tillgänglig från: 2011-03-31 Skapad: 2011-03-31 Senast uppdaterad: 2016-03-03
    9. Reliable model for the calculation of negative leader discharges under switching impulses
    Öppna denna publikation i ny flik eller fönster >>Reliable model for the calculation of negative leader discharges under switching impulses
    2010 (Engelska)Konferensbidrag, Publicerat paper (Refereegranskat)
    Nyckelord
    negative streamer, space leader, breakdown
    Nationell ämneskategori
    Annan elektroteknik och elektronik
    Forskningsämne
    Teknisk fysik med inriktning mot atmosfäriska urladdningar
    Identifikatorer
    urn:nbn:se:uu:diva-150533 (URN)
    Konferens
    36th grounding and 4th Lightning Physics conference GND&LPE
    Tillgänglig från: 2011-03-31 Skapad: 2011-03-31 Senast uppdaterad: 2016-04-18
    10. A preliminary model to simulate negative leader discharges
    Öppna denna publikation i ny flik eller fönster >>A preliminary model to simulate negative leader discharges
    (Engelska)Ingår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463Artikel i tidskrift (Refereegranskat) Submitted
    Nyckelord
    Negative streamer, pilot system, breakdown
    Nationell ämneskategori
    Annan elektroteknik och elektronik
    Forskningsämne
    Teknisk fysik med inriktning mot atmosfäriska urladdningar
    Identifikatorer
    urn:nbn:se:uu:diva-150532 (URN)
    Tillgänglig från: 2011-03-31 Skapad: 2011-03-31 Senast uppdaterad: 2017-12-11
    11. On the interception of lightning flashes by power transmission lines
    Öppna denna publikation i ny flik eller fönster >>On the interception of lightning flashes by power transmission lines
    2011 (Engelska)Ingår i: Journal of Electrostatics, ISSN 0304-3886, E-ISSN 1873-5738, Vol. 69, nr 3, s. 220-227Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    The design of the lightning protection system LPS of transmission lines is based on the well knownelectro-geometrical model. The electro-geometrical model assumes that the first point on a powertransmission line that will come within striking distance of the tip of a down-coming stepped leaderchannel is the strike point of the lightning flash. The model neglects almost all of the physics associatedwith the lightning attachment.Nowadays, as it is possible to use modern hardware and software tools and several different numericalmethods, it is feasible to apply the physics of the discharge process to the study of lightning attachment.Such models take into account the movement of the downward and the resulting upward leaders fromdifferent points on the structures under consideration.In this paper, a procedure based on lightning physics was used to analyze the lightning attachmentphenomena in EHV transmission lines of 230 kV and 500 kV and the results were compared with thepredictions of the electro-geometrical method.

    Nyckelord
    power system, lightning attachment, breakdown, downward leader
    Nationell ämneskategori
    Annan elektroteknik och elektronik
    Forskningsämne
    Teknisk fysik med inriktning mot atmosfäriska urladdningar
    Identifikatorer
    urn:nbn:se:uu:diva-150534 (URN)10.1016/j.elstat.2011.03.013 (DOI)000292230300012 ()
    Tillgänglig från: 2011-03-31 Skapad: 2011-03-31 Senast uppdaterad: 2017-12-11
    12. 'The mesh method' in lightning protection standards - Revisited
    Öppna denna publikation i ny flik eller fönster >>'The mesh method' in lightning protection standards - Revisited
    2010 (Engelska)Ingår i: Journal of Electrostatics, ISSN 0304-3886, E-ISSN 1873-5738, Vol. 68, nr 4, s. 311-314Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    At present the design of the Lightning protection systems (LPS) for structures as stipulated in standards is based on the electro - geometrical method, which was initially used to protect power lines from lightning. A derivative of the electro-geometrical method is the rolling sphere method. This method together, with the protection angle method and mesh method are used almost in all lightning standards as the measure in installing the lightning protection systems of grounded structures. In the mesh method, the dimension of the cell size in different levels of protection is determined using the rolling sphere method. Since the rolling sphere method does not take into account the physics of the lightning attachment process there is a need to evaluate the validity of the stipulated value in standards of the minimum lightning current that can penetrate through the mesh in different levels of protection. In this paper, meshes of different sizes as stipulated in the lightning protection standards were tested for their ability to intercept lightning flashes using a lightning attachment model that takes into account the physics of connecting leaders on. The results are in reasonable agreement with the specifications given in the lightning protection standards.

    Nyckelord
    Dynamic leader, Electro-geometrical method, Lightning inception, Mesh method, Upward leader, Standards
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:uu:diva-135183 (URN)10.1016/j.elstat.2010.03.003 (DOI)000281211700004 ()
    Tillgänglig från: 2010-12-06 Skapad: 2010-12-06 Senast uppdaterad: 2017-12-12Bibliografiskt granskad
    13. Influence of multiple upward connecting leaders initiated from the same structure on the lightning attachment process
    Öppna denna publikation i ny flik eller fönster >>Influence of multiple upward connecting leaders initiated from the same structure on the lightning attachment process
    2009 (Engelska)Konferensbidrag, Publicerat paper (Refereegranskat)
    Nyckelord
    electric field, inhibit discharge, breakdown, streamer, lightning, attachment
    Nationell ämneskategori
    Annan elektroteknik och elektronik
    Forskningsämne
    Teknisk fysik med inriktning mot atmosfäriska urladdningar
    Identifikatorer
    urn:nbn:se:uu:diva-150535 (URN)
    Konferens
    X International symposium on lightning protection - SIPDA
    Tillgänglig från: 2011-03-31 Skapad: 2011-03-31 Senast uppdaterad: 2016-04-14
    14. Interaction of multiple connecting leaders issued from a grounded structure simulated using a self consistent leader inception and propagation model SLIM
    Öppna denna publikation i ny flik eller fönster >>Interaction of multiple connecting leaders issued from a grounded structure simulated using a self consistent leader inception and propagation model SLIM
    2010 (Engelska)Ingår i: 30TH International Conference on Lightning Protection, ICLP, Cagliary, Italy, 2010Konferensbidrag, Publicerat paper (Refereegranskat)
    Ort, förlag, år, upplaga, sidor
    Cagliary, Italy: , 2010
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:uu:diva-142452 (URN)
    Konferens
    30TH International Conference on Lightning Protection, ICLP
    Tillgänglig från: 2011-01-14 Skapad: 2011-01-14 Senast uppdaterad: 2016-04-19Bibliografiskt granskad
  • 31.
    Arevalo, Liliana
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Cooray, Vernon
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    A preliminary model to simulate negative leader dischargesIngår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463Artikel i tidskrift (Refereegranskat)
  • 32.
    Arevalo, Liliana
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Cooray, Vernon
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Influence of multiple upward connecting leaders initiated from the same structure on the lightning attachment process2009Konferensbidrag (Refereegranskat)
  • 33.
    Arevalo, Liliana
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Cooray, Vernon
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    On the interception of lightning flashes by power transmission lines2011Ingår i: Journal of Electrostatics, ISSN 0304-3886, E-ISSN 1873-5738, Vol. 69, nr 3, s. 220-227Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The design of the lightning protection system LPS of transmission lines is based on the well knownelectro-geometrical model. The electro-geometrical model assumes that the first point on a powertransmission line that will come within striking distance of the tip of a down-coming stepped leaderchannel is the strike point of the lightning flash. The model neglects almost all of the physics associatedwith the lightning attachment.Nowadays, as it is possible to use modern hardware and software tools and several different numericalmethods, it is feasible to apply the physics of the discharge process to the study of lightning attachment.Such models take into account the movement of the downward and the resulting upward leaders fromdifferent points on the structures under consideration.In this paper, a procedure based on lightning physics was used to analyze the lightning attachmentphenomena in EHV transmission lines of 230 kV and 500 kV and the results were compared with thepredictions of the electro-geometrical method.

  • 34.
    Arevalo, Liliana
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Cooray, Vernon
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Reliable model for the calculation of negative leader discharges under switching impulses2010Konferensbidrag (Refereegranskat)
  • 35.
    Arevalo, Liliana
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Cooray, Vernon
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Wu, Dong
    Jacobson, Björn
    The development of long spark gaps: Simulation including a variable streamer regionArtikel i tidskrift (Refereegranskat)
  • 36.
    Arevalo, Liliana
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Wu, Dong
    ABB Power Systems HVDC.
    A consistent approach to estimate the breakdown voltage of high voltage electrodes under positive switching impulses2013Ingår i: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 114, nr 8Artikel i tidskrift (Refereegranskat)
  • 37.
    Arevalo, Liliana
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära. ABB Power Systems HVDC.
    Wu, Dong
    ABB Power Systems HVDC.
    Coated large electrodes for corona prevention2013Ingår i: International Symposium on High Voltage Engineering ISH, At Seoul Korea, 2013Konferensbidrag (Refereegranskat)
  • 38.
    Arevalo, Liliana
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära. ABB Power Systems HVDC.
    Wu, Dong
    ABB POwer Systems HVDC.
    INFLUENCE OF RAIN ON THE SWITCHING IMPULSE BREAKDOWN BEHAVIOUR OF POST INSULATOR WITH LARGE ELECTRODE2013Ingår i: CIGRE Symposium "Best practice in generation, transmission and distribution in a changing environment", At Auckland, New Zealand / [ed] CIGRE, 2013Konferensbidrag (Refereegranskat)
  • 39.
    Arvidsson, Mari
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Analys av mellanspänningsnätet i centrala delar av Västerås stad2015Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The dependency of continuous electricity supply is high in the Swedish society today, at the same time no one is willing to pay for a too costly or over dimensioned power distribution system. The owners of the distribution systems are the ones responsible for this balance act of maintaining a high quality of electricity delivery to customers at a reasonable cost.

    In this master thesis a limited part of the primary distribution system (10 kV), owned by Mälarenergi Elnät AB and located in the city centre of Västerås, was chosen for a deeper analysis of its reliability. Its ability to handle outages of system components (N-1 and N-2 contingency analysis) was investigated to find out potential weak spots and parts of the grid that showed signs of being overdimensioned.

    The results of the performed simulations showed that in 74 % of the studied N-1 contingencies cases, consisting of outages of a bus bar in a distribution substation, the system could handle this without causing outages in other parts of the grid. For the N-2 contingencies 61 % passed the test. It was also found that one of the two included high voltage substations could alone supply the investigated part of the grid. Some cables and transformers were found to be more or less unnecessary, whereas other components proved to be overloaded in several situations.

  • 40. Ask, Simon
    et al.
    Lindh, Rickard
    Design och konstruktion av roterande LiDAR-system för 360 graders objektdetektering2017Självständigt arbete på grundnivå (yrkesexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Although laser rangefinder technologies have been around for decades in military, cartography, building, industrial and research applications it is only in recent years that more generally applicable and cheaper consumer grade laser range finder sensors have become available. This project investigates the possibilities and limitations of creating a mobile 360 degree, two-dimensional obstacle detection system using off-the-shelf available electronic components.

    Using a Lidar Lite 3 from Garmin Ltd., an Arduino compatible microcontroller based on Atmel 328P, a Raspberry Pi 3 from The Raspberry Pi Foundation and an electronic speed controlled brushless DC motor driving the rotation, it is shown how range data measurements can be collected, communicated, processed and displayed at measurement rates between 500 and 1000 Hz. At 5 Hz update rate of a complete 360-degree data set, this translates to a worst case angular resolution of 2.5 degrees at ranges reaching 10 meters depending on target reflectivity. Configured for these faster measurement rates, at static measurements of a white painted wall, the measurements show a standard deviation of 0.06 m at a five-meter range, going up to 0.19 m at a range of 10 meters.

    A modular and mobile prototype was designed and built. The modularity allowed testing and verification of two configurations. Configuration A uses a slip ring for power and data transfer to the rotating sensor. Configuration B allows the laser range finder to be stationary and instead rotates a first surface aluminum mirror positioned at 45 degrees above the sensor.

    The measurement results show that increasing range has a notable adversely effect on the number of successful readings in a setting demanding faster measurement rates of above 500 Hz. The number of successful readings decreases at ranges above 5 meters, and this decrease of successful readings is more pronounced in the configuration using a mirror to reflect the measurement. The mirror reflected version does on the other hand allow an electromechanically simpler, more silent and durable system.

    Using a density based clustering algorithm it is shown how person sized objects in the point cloud data can be robustly detected at ranges up to 5 meters. 

  • 41.
    Augustine, Robin
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Rydberg, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Complex dielectric permittivity measurements of human skin and biological solution in 2-67GHz range2012Konferensbidrag (Refereegranskat)
  • 42.
    Avramov, Ivan
    et al.
    Bulgarian Academy of Sciences.
    Arapan, Lilia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Katardjiev, Ilia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Strashilov, Vesseline
    University of Sofia.
    Yantchev, Ventsislav
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    IC-compatible Power Oscillators Using Thin Film Plate Acoustic Resonator (FPAR)2009Ingår i: Proceedings 2009 IEEE International Ultrasonics Symposium, 2009Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this study, two-port 880MHz FPAR devicesoperating on the lowest order fast symmetric Lamb wave mode(S0) in c-oriented AlN membranes on Si, were fabricated andsubsequently tested for their power handling capabilities in afeedback-loop power oscillator circuit. The S0 Lamb waves wereexcited and detected by a classical two-port resonator structure,as in Rayleigh SAW (RSAW) resonators. Incident power levels ofup to 24 dBm (250 mW) for the FPARs were provided by a high powersustaining amplifier in the loop. No measurable performance degradation was observed. The results from this study indicate that IC-compatible S0 FPAR devices can dissipate orders of magnitude higher RF-power levels than their RSAWcounterparts on quartz and are well suited for integrated microwave power oscillators with thermal noise floor (TNF) levelsbelow -175 dBc/Hz.

  • 43.
    Ayob, Mohd Nasir
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Castellucci, Valeria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Abrahamsson, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Svensson, Olle
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Waters, Rafael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Control Strategy for a Tidal Compensation System for Wave Energy Converter Device2018Konferensbidrag (Refereegranskat)
  • 44.
    Aziz, Imran
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik. Mirpur University of Science & Technology (MUST), Pakistan.
    Dancila, Dragos
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Dittmeier, Sebastian
    Heidelberg Univ, Heidelberg, Germany.
    Siligaris, Alexandre
    CEA Leti, Grenoble, France.
    Dehos, Cedric
    CEA Leti, Grenoble, France.
    De Lurgio, Patrik Martin
    Argonne Lab, Lemont, IL USA.
    Djurcic, Zelimir
    Argonne Lab, Lemont, IL USA.
    Drake, Gary
    Argonne Lab, Lemont, IL USA.
    Jimenez, Jose Luis Gonzalez
    CEA Leti, Grenoble, France.
    Gustafsson, Leif
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Kim, Don-Won
    Gangneung Wonju Univ, Kangnung, South Korea.
    Locci, Elizabeth
    CEA DSM IRFU DphP, Paris, France;Paris Saclay Univ, Paris, France.
    Pfeiffer, Ulrich
    Wuppertal Univ, Wuppertal, Germany.
    Vazquez, Pedro Rodriquez
    Wuppertal Univ, Wuppertal, Germany.
    Rohrich, Dieter
    Bergen Univ, Bergen, Norway.
    Schoening, Andre
    Heidelberg Univ, Heidelberg, Germany.
    Soltveit, Hans Kristian
    Heidelberg Univ, Heidelberg, Germany.
    Ullaland, Kjetil
    Bergen Univ, Bergen, Norway.
    Vincent, Pierre
    CEA Leti, Grenoble, France.
    Yang, Shiming
    Bergen Univ, Bergen, Norway.
    Brenner, Richard
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Effects of proton irradiation on 60 GHz CMOS transceiver chip for multi-Gbps communication in high-energy physics experiments2019Ingår i: The Journal of Engineering, ISSN 1872-3284, E-ISSN 2051-3305, nr 8, s. 5391-5396Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This article presents the experimental results of 17 MeV proton irradiation on a 60 GHz low power, half-duplex transceiver (TRX) chip implemented in 65 nm CMOS technology. It supports short range point-to-point data rate up to 6 Gbps by employing on-off keying (OOK). To investigate the irradiation hardness for high-energy physics (HEP) applications, two TRX chips were irradiated with total ionising doses (TID) of 74 and 42 kGy and fluence of 1.4 x 10(14)N(eq)/cm(2) and 0.8 x 10(14)N(eq)/cm(2) for RX and TX modes, respectively. The chips were characterised by pre- and post-irradiation analogue voltage measurements on different circuit blocks as well as through the analysis of wireless transmission parameters like bit error rate (BER), eye diagram, jitter etc. Post-irradiation measurements have shown certain reduction in performance but both TRX chips have been found operational through over the air measurements at 5 Gbps. Moreover, very small shift in the carrier frequency was observed after the irradiation.

  • 45.
    Back, Erik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    A new DC-DC converter technology suitable to support grid connection of wave power energy converter2012Självständigt arbete på grundnivå (yrkesexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Since 2002, the department of electricity at Uppsala university has pushed the Lysekil project. The project has a number of wave energy converters installed in the sea southwest of Lysekil.

    The purpose of this work is to design, build and test a DC-DC converter, which will later be used as a necessary part of the grid connection of a wave energy converter.

    Since a wave energy converter does not generate electricity at a constant frequency, it is not possible to use a gearbox. Instead, power is rectified and, if there are several wave power energy converters, are put together with the others before it is inverted and transformed to the correct voltage level, and finally connected to the grid [1].

    The designed DC-DC converter is a converter of the type "inverting buck-boost", i.e. a converter that can both lower and raise the voltage, and inverts the polarity of the output. Although the voltage in normal circumstances will only be increased, the simulations showed that the efficiency and cost of components did not differ much between a "boost" and "buck-boost" converter, thus considered flexibility to be able to lower the voltage if needed.

    The project also includes a small part to the construction of a bridge rectifier, but as the most difficult moment in the project is the DC-DC converter, the greatest focus will be there.

  • 46.
    Backlund, Andreas
    et al.
    GE Healthcare.
    Dancila, Dragos
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    RADIOFREQUENCY POWER COMBINER OR DIVIDER HAVING A TRANSMISSION LINE RESONATOR2018Patent (Övrig (populärvetenskap, debatt, mm))
  • 47.
    Backlund, Andreas
    et al.
    GE Healthcare.
    Dancila, Dragos
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    SYSTEM AND METHOD FOR AMPLIFIYING AND COMBINING RADIOFREQUENCY POWER2018Patent (Övrig (populärvetenskap, debatt, mm))
  • 48.
    Backlund, Ludvig
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    Martin, Anna
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    Svantesson, Gustaf
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    Methods for calibration of the vibration measurement system EVME used on the JAS 39 Gripen engine.2014Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    This project investigates methods for calibrating and functional testing an Engine Vibration Measurement Equipment. The equipment uses accelerometers to measure vibrations on the JAS 39 Gripen aircraft engine to ensure that the engine is correctly installed. A model for emulating the electronic signals generated by the accelerometers was created in Simulink and different ways for utilizing the model as a part of a complete test system were examined. Upon examination of different calibration methods it was found that a complete test system needs to have the ability to both send electrical signals directly into the EVME as well as a way of testing the accelerometers mechanically. Both short- and long-term solutions fulfilling these requirements were prepared.

  • 49.
    Baharin, S. A. S.
    et al.
    Univ Tekn Malaysia Melaka UTeM, Ctr Telecommun Res & Innovat CeTRI, Atmospher & Lightning Res Lab, Fa Kejuruteraan Elekt & Kejuruteraan Komputer, Durian Tunggal 76100, Melaka, Malaysia.
    Ahmad, M. R.
    Univ Tekn Malaysia Melaka UTeM, Ctr Telecommun Res & Innovat CeTRI, Atmospher & Lightning Res Lab, Fa Kejuruteraan Elekt & Kejuruteraan Komputer, Durian Tunggal 76100, Melaka, Malaysia.
    Periannan, D.
    Univ Tekn Malaysia Melaka UTeM, Ctr Telecommun Res & Innovat CeTRI, Atmospher & Lightning Res Lab, Fa Kejuruteraan Elekt & Kejuruteraan Komputer, Durian Tunggal 76100, Melaka, Malaysia.
    Sabri, M. H. M.
    Univ Tekn Malaysia Melaka UTeM, Ctr Telecommun Res & Innovat CeTRI, Atmospher & Lightning Res Lab, Fa Kejuruteraan Elekt & Kejuruteraan Komputer, Durian Tunggal 76100, Melaka, Malaysia.
    Seah, B. Y.
    Univ Tekn Malaysia Melaka UTeM, Ctr Telecommun Res & Innovat CeTRI, Atmospher & Lightning Res Lab, Fa Kejuruteraan Elekt & Kejuruteraan Komputer, Durian Tunggal 76100, Melaka, Malaysia.
    Aziz, M. Z. A. A.
    Univ Tekn Malaysia Melaka UTeM, Ctr Telecommun Res & Innovat CeTRI, Atmospher & Lightning Res Lab, Fa Kejuruteraan Elekt & Kejuruteraan Komputer, Durian Tunggal 76100, Melaka, Malaysia.
    Ismail, M. M.
    Univ Tekn Malaysia Melaka UTeM, Ctr Telecommun Res & Innovat CeTRI, Atmospher & Lightning Res Lab, Fa Kejuruteraan Elekt & Kejuruteraan Komputer, Durian Tunggal 76100, Melaka, Malaysia.
    Esa, M. R. M.
    Univ Teknol Malaysia, FKE, Inst High Voltage & High Current IVAT, Johor Baharu 81310, Johor, Malaysia.
    Mohammad, S. A.
    Univ Teknol Malaysia, FKE, Inst High Voltage & High Current IVAT, Johor Baharu 81310, Johor, Malaysia.
    Abdul-Malek, Z.
    Univ Teknol Malaysia, FKE, Inst High Voltage & High Current IVAT, Johor Baharu 81310, Johor, Malaysia.
    Yusop, N.
    Univ Kebangsaan Malaysia, Inst Climate Change, Space Sci Ctr ANGKASA, Bangi 43600, Selangor Darul, Malaysia.
    Cooray, Vernon
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Lu, G.
    Chinese Acad Sci, Inst Atmospher Phys, Key Lab Middle Atmosphere & Global Environm Obser, Beijing, Peoples R China.
    Wavelet Analysis of the Onset of VHF and Microwave Radiation Emitted by Lightning2018Ingår i: 2018 INTERNATIONAL CONFERENCE ON ELECTRICAL ENGINEERING AND COMPUTER SCIENCE (ICECOS), IEEE , 2018, s. 297-300Konferensbidrag (Refereegranskat)
    Abstract [en]

    Lightning flash is an electrical discharge in air (dielectric breakdown) which emits electromagnetic (FM) fields across very wide spectra from a few Hertz up to visible wavelength. Electrical breakdown process is an important event that initiates lightning. For electrical breakdown process to occur, it must fulfill two conditions which are at least has one free electron and the electric field region is more than 3 MV/m. This process starts with electron avalanche in millimeter scale then grows into streamer in centimeter scale. Lastly, from streamer it will grow into leader in meter scale. It has already established that streamer emits intensely at Very High Frequency (VHF) band as it's already proven both theoretically and experimentally. A study by Cooray, theoretically proved that emission of electron avalanche peaks at microwave band. Air-gap parallel plate antenna which could operate at 1 GHz with remote sensing is designed and simulated to measure the microwave radiation emitted by lightning. Both temporal and wavelet analyses are used to compare the onset of microwave radiation and VHF radiation in both time and frequency domains to determine electron avalanche appears at which electromagnetic band.

  • 50.
    Baharudin, Zikri Abadi
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Characterizations of ground flashes from tropic to northern region2014Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    This thesis portrays new information concerning the cloud-to-ground (CG) lightning flashes or ground flashes produced by thunderclouds. It emphasizes the importance of characterizing lightning studies as the relationship between lightning mechanisms, and of incorporating the influence of geographical location, latitude and storm type. Sweden, Malaysia and USA were chosen as the main locations for field experiments in 2009 to 2011 to gather a significant number of negative and positive CG flashes. This work provided data on a total of 1792 CG lightning flashes (1685 negative and 107 positive ones) from a total of 53 thunderstorms by monitoring both the slow and the fast electric field and the narrowband radiation field at 3 and 30 MHz signals simultaneously. This thesis is comprised of: (i) the relationship of the Low Positive Charge Region (LPCR) and Preliminary Breakdown Pulse (PBP) trains to the occurrence of negative CG, (ii) slow field changes generated by preliminary breakdown processes in positive and negative ground flashes, and (iii) the occurrence of positive and negative ground flashes. It was revealed that the PBP train appeared have a higher strength in the in Sweden. The strength of the PBP train was caused by the LPCR; in contrast,  weak PBP trains were characteristic in tropical countries constituting insignificant LPCR and needing little energy to break the “blocking” agent to allow the flash to propagate downward to the ground. The second contribution concerns the characteristics of the PBP train mentioned; this includes novel information for Malaysia. Further, it is stated that there are some different characteristics in the PBP trains in Johor, Malaysia and Florida, USA. The studies of slow field changes generated by preliminary breakdown processes clarifies unclear features concerning the starting position of slow field changes generated by preliminary breakdown processes in positive and negative ground flashes. It was found that the slow field changes did not occur before the initial process of the commencement of preliminary breakdown. Single-station electric field measurements incorporating narrowband radiation field measurement and high resolution transient recording (12 bits) with an accuracy of several nanoseconds, allows one to distinguish between the intracloud activities and the preceding processes of ground flashes. The results for the interstroke intervals, amplitude distribution of subsequent return-stroke (SRS) and the number of strokes per flash in the tropics, subtropics and northern regions were similar. Finally, a significant number of positive return-stroke (RS) electric fields provided statistically significant information on the characteristics of these strokes.

    Delarbeten
    1. Comparative study on preliminary breakdown pulse trains observed in Johor, Malaysia and Florida, USA
    Öppna denna publikation i ny flik eller fönster >>Comparative study on preliminary breakdown pulse trains observed in Johor, Malaysia and Florida, USA
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    2012 (Engelska)Ingår i: Atmospheric research, ISSN 0169-8095, E-ISSN 1873-2895, Vol. 117, s. 111-121Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    In this paper, the preliminary breakdown (PB) pulse train preceding the negative first return stroke (RS) is recorded using a broad band antenna system. These analyses were carried out in Johor Bahru, Malaysia and Florida, United States. This is a novel initiative at examining and identifying the characteristics of the PB pulse trains in the negative cloud-to-ground flashes observed in Malaysia. The arithmetic mean of the total pulse train duration is 12.3 ms and the weighted arithmetic mean of the pulse durations and interpulse intervals are 11 mu s and 152 mu s, respectively. The arithmetic mean ratio between the maximum peak amplitude of the PB pulse and the peak RS electric field was 27.8%, and the corresponding value in Florida was 29.4%. The arithmetic mean of the time duration between the most active part of the pulse train, and the RS was 57.6 ms in Malaysia and 22 ms in Florida. A qualitative comparison of our results with those obtained earlier in Sri Lanka. Sweden and Finland supports the hypothesis that the PBP/RS ratio is higher in the northern regions compared to the tropical regions. (C) 2012 Elsevier B.V. All rights reserved.

    Nyckelord
    Preliminary breakdown pulses, PB/RS ratio, PB-RS separation
    Nationell ämneskategori
    Teknik och teknologier
    Forskningsämne
    Teknisk fysik med inriktning mot elektricitetslära
    Identifikatorer
    urn:nbn:se:uu:diva-184450 (URN)10.1016/j.atmosres.2012.01.012 (DOI)000309300100015 ()
    Tillgänglig från: 2012-11-09 Skapad: 2012-11-07 Senast uppdaterad: 2017-12-07Bibliografiskt granskad
    2. Electric field changes generated by the preliminary breakdown for the negative cloud-to-ground lightning flashes in Malaysia and Sweden
    Öppna denna publikation i ny flik eller fönster >>Electric field changes generated by the preliminary breakdown for the negative cloud-to-ground lightning flashes in Malaysia and Sweden
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    2012 (Engelska)Ingår i: Journal of Atmospheric and Solar-Terrestrial Physics, ISSN 1364-6826, E-ISSN 1879-1824, Vol. 84-85, s. 15-24Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    We present the study of the electric field changes generated by the preliminary breakdown for negative cloud-to-ground lightning flashes in Malaysia and Sweden concerning the association of slow field changes associated in preliminary breakdown process. We examined the total of 1685 negative cloud-to-ground lightning flashes from the total of 39 thunderstorms by recording the slow electric field, fast electric field and narrowband radiation field at 3 and 30 MHz signals simultaneously. Our results show that there is a pre-starting time, i.e. the duration between the first preliminary breakdown pulse and slow field changes starting point, which is found to be after the first preliminary breakdown pulse. The pre-starting time has the arithmetic and geometric mean range from 1.4-6.47 and 1-3.36 ms, respectively. The mean values of pre-starting time in Malaysia are greater than the values observed in Sweden by more than a factor of 3. From the two data sets it shows that the slow field changes never start before the preliminary breakdown. Furthermore, the use of single-station electric fields measurement with high resolutions of 12 bits transient recorder with several nanosecond accuracy allow one to distinguish the slow field changes generated by preliminary breakdown, which preceded the negative first return stroke, between tens to hundreds of milliseconds of pre-return stroke duration.

    Nyckelord
    Initiation position, Slow field changes, Close ground flashes, Preliminary breakdown process
    Nationell ämneskategori
    Meteorologi och atmosfärforskning Teknik och teknologier
    Forskningsämne
    Teknisk fysik med inriktning mot atmosfäriska urladdningar
    Identifikatorer
    urn:nbn:se:uu:diva-182547 (URN)10.1016/j.jastp.2012.04.009 (DOI)000308512100003 ()
    Tillgänglig från: 2012-10-11 Skapad: 2012-10-11 Senast uppdaterad: 2017-12-07
    3. Electric field changes generated by preliminary breakdown pulse for positive lightning ground flashes in Sweden
    Öppna denna publikation i ny flik eller fönster >>Electric field changes generated by preliminary breakdown pulse for positive lightning ground flashes in Sweden
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    (Engelska)Manuskript (preprint) (Övrigt vetenskapligt) [Forskning på konstnärlig grund]
    Abstract [en]

    This is the new study of the electric field changes generated by the preliminary breakdown for positive cloud-to-ground flashes which concerning on the association of slow field changes in preliminary breakdown process. In this study, a 107 positive cloud-to-ground lightning flashes recorded from the total of 14 thunderstorms generated by the whole flash were examined. The electric fields were measured with nanosecond resolution by using the slow electric field, fast electric field and narrowband radiation field at 3 and 30 MHz signals simultaneously. Our result shows that there is a pre-starting time, i.e. the duration between the first preliminary breakdown pulse and slow field changes starting point, which is found to be after the first preliminary breakdown pulse. The pre-starting time has the arithmetic mean – 3.0 ms and geometric mean – 1.8 ms, ranging from 0.3 to 21.7 ms. This study is consistent with the latest finding for the slow field changes in negative ground flashes where the slow field changes never start before the preliminary breakdown process.

    Nyckelord
    Positive cloud-to-ground lightning flashes, Initiation position, slow field changes, close ground flashes, preliminary breakdown process
    Nationell ämneskategori
    Annan elektroteknik och elektronik
    Forskningsämne
    Teknisk fysik med inriktning mot atmosfäriska urladdningar
    Identifikatorer
    urn:nbn:se:uu:diva-222826 (URN)
    Forskningsfinansiär
    Vetenskapsrådet, 621-2006-4299Stiftelsen för strategisk forskning (SSF), IG2004–2031
    Tillgänglig från: 2014-04-15 Skapad: 2014-04-14 Senast uppdaterad: 2017-11-09Bibliografiskt granskad
    4. Negative cloud-to-ground lightning flashes in Malaysia
    Öppna denna publikation i ny flik eller fönster >>Negative cloud-to-ground lightning flashes in Malaysia
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    2014 (Engelska)Ingår i: Journal of Atmospheric and Solar-Terrestrial Physics, ISSN 1364-6826, E-ISSN 1879-1824, Vol. 108, s. 61-67Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    The characteristics of the negative cloud-to-ground lightning flashes in Malaysia are studied by analyzing the electric fields generated by the whole flash in nanosecond resolution. A total of 405 strokes obtained from 100 successive negative cloud-to-ground lightning flashes were analyzed, which were recorded from seven convective thunderstorms during the southwest monsoon period, i.e. from April to June 2009. It was found that the total number of interstroke intervals has an arithmetic mean value of 86 ms, a geometric mean value of 67 ms and does not depend on the return stroke order. Of the 100 negative ground flashes, 38 flashes (38%) have at least one subsequent return-stroke (SRS) whose electric field peak was greater than that of the first return-stroke (RS). Furthermore, 58 (19%) out of 305 SRS have electric field peak larger than those of the first RS. The arithmetic and geometric mean ratio between the peak electric field of the SRS and the peak electric field of the first RS are 0.7 and 0.6, respectively. The percentage of single-stroke flashes was 16% while the mean number of strokes per flash and maximum number of stroke per flash were 4 and 14, respectively.

    Nyckelord
    Negative cloud-to-ground lightning flashes, Number of strokes per flash and interstroke interval
    Nationell ämneskategori
    Naturvetenskap Teknik och teknologier
    Forskningsämne
    Teknisk fysik med inriktning mot elektricitetslära
    Identifikatorer
    urn:nbn:se:uu:diva-221965 (URN)10.1016/j.jastp.2013.12.001 (DOI)000331684900007 ()
    Tillgänglig från: 2014-04-10 Skapad: 2014-04-07 Senast uppdaterad: 2017-12-05Bibliografiskt granskad
    5. On the characteristics of positive lightning ground flashes in Sweden
    Öppna denna publikation i ny flik eller fönster >>On the characteristics of positive lightning ground flashes in Sweden
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    2016 (Engelska)Ingår i: Journal of Atmospheric and Solar-Terrestrial Physics, ISSN 1364-6826, E-ISSN 1879-1824, Vol. 138, s. 106-111Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    In this study the stroke characteristics of positive cloud-to-ground flashes in Sweden were obtained from the electric field records measured from 14 thunderstorms. The electric fields were measured with nanosecond resolution. Together with the fast and the slow electric field records, the narrowband radiation field at 3 and 30 MHz signals were also measured simultaneously. Out of a total of 107 flashes, 30 flashes had two strokes, 7 had three strokes and 3 flashes had four strokes. The arithmetic and geometric means of the interstroke intervals were found to be 116 and 70 ms, respectively. The arithmetic and geometric mean ratio between the peak electric field of the Subsequent Return Stroke (SRS) and the first Return Stroke (RS) were 0.48 and 0.36, respectively. Of the 40 positive multiple-stroke ground flashes, 5% have at least one SRS with field peak higher than the first RS. The percentage of SRS with field peaks greater than the first RS was 6%. In our best of our knowledge, this is the first time a large sample of positive return strokes in Sweden was analysed. It was found to be statistically more significant than the previous studies.

    Nyckelord
    Lightning flashes, Positive ground flashes, Positive return strokes, Electromagnetic fields
    Nationell ämneskategori
    Meteorologi och atmosfärforskning Teknik och teknologier
    Forskningsämne
    Teknisk fysik med inriktning mot atmosfäriska urladdningar
    Identifikatorer
    urn:nbn:se:uu:diva-274994 (URN)10.1016/j.jastp.2015.12.014 (DOI)000370769900011 ()
    Forskningsfinansiär
    Vetenskapsrådet, 621-2006-4299
    Tillgänglig från: 2016-01-27 Skapad: 2016-01-27 Senast uppdaterad: 2017-11-30Bibliografiskt granskad
    6. Comparative Study on Preliminary Breakdown Pulse Trains Observed in Malaysia and Florida
    Öppna denna publikation i ny flik eller fönster >>Comparative Study on Preliminary Breakdown Pulse Trains Observed in Malaysia and Florida
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    2010 (Engelska)Konferensbidrag, Publicerat paper (Refereegranskat)
    Ort, förlag, år, upplaga, sidor
    Cagliary, Italy: , 2010
    Nationell ämneskategori
    Teknik och teknologier
    Forskningsämne
    Teknisk fysik med inriktning mot atmosfäriska urladdningar
    Identifikatorer
    urn:nbn:se:uu:diva-140393 (URN)
    Konferens
    30TH International Conference on Lightning Protection, ICLP
    Tillgänglig från: 2011-01-05 Skapad: 2011-01-05 Senast uppdaterad: 2018-05-28