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Efficient RF voltage transformer with bandpass filter characteristics
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics. (Thin Films Group)
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics. (Thin Films Group)
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics. (Thin Films Group)
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics. (Thin Films Group)
2013 (English)In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 49, no 3, 198-199 p.Article in journal (Refereed) Published
Abstract [en]

A microwave bandpassfilter with a large ratio between the output andthe input impedance has been designed and fabricated. Consequently,it functions both as a voltage transformer and a bandpassfilter, or trans-filter for brevity. It represents a two-port micro-acoustic resonatoremploying Lamb waves in a thin piezoelectric AlNfilm grown ontoa Si carrier substrate with a centre frequency of around 887 MHz.The transfilter has a transformer ratio of 10 and a voltage efficiencyof over 80%. The component has a small size ( < 0.5 mm2) and isshown to sustain power levels of 250 mW. It can be used in avariety of cases where both voltage amplification and frequencyfilter-ing are required. Examples include: charge pumps in RFID tags,energy scavenging, remotely triggered switches, wake-up radios inwireless networks, stand-by units in home electronics etc.

Place, publisher, year, edition, pages
iet , 2013. Vol. 49, no 3, 198-199 p.
Keyword [en]
wireless, Lamb wave, trasnformer, RF
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Engineering Science with specialization in Microsystems Technology; Engineering Science with specialization in Electronics
Identifiers
URN: urn:nbn:se:uu:diva-185262DOI: 10.1049/el.2012.3982ISI: 000318542500023OAI: oai:DiVA.org:uu-185262DiVA: diva2:571094
Projects
WiSENET and VR granted "Thin Film Guided Microacoustic Waves in Periodical Systems: Theory and Applications "
Funder
VinnovaSwedish Research Council, 2009-5056
Available from: 2012-11-21 Created: 2012-11-21 Last updated: 2017-12-07Bibliographically approved
In thesis
1. Synthesis of Thin Piezoelectric AlN Films in View of Sensors and Telecom Applications
Open this publication in new window or tab >>Synthesis of Thin Piezoelectric AlN Films in View of Sensors and Telecom Applications
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The requirements of the consumer market on high frequency devices have been more and more demanding over the last decades. Thus, a continuing enhancement of the devices’ performance is required in order to meet these demands. In a macro view, changing the design of the device can result in an improvement of its performance. In a micro view, the physical properties of the device materials have a strong influence on its final performance. In the case of high frequency devices based on piezoelectric materials, a natural way to improve their performance is through the improvement of the properties of the piezoelectric layer. The piezoelectric material studied in this work is AlN, which is an outstanding material among other piezoelectric materials due to its unique combination of material properties.

This thesis presents results from experimental studies on the synthesis of AlN thin films in view of telecom, microelectronic and sensor applications. The main objective of the thesis is to custom design the functional properties of AlN to best suit these for the specific application in mind. This is achieved through careful control of the crystallographic structure and texture as well as film composition.

The piezoelectric properties of AlN films were enhanced by doping with Sc. Films with different Sc concentrations were fabricated and analyzed, and the coupling coefficient (kt2) was enhanced a factor of two by adding 15% of Sc to the AlN films. The enhancement of kt2 is of interest since it can contribute to a more relaxed design of high frequency devices. Further, in order to obtain better deposition control of c-axis tilted AlN films, a new experimental setup were proposed. When this novel setup was used, films with well-defined thicknesses and tilt uniformity were achieved. Films with such characteristics are very favorable to use in sensors based on electroacoustic devices operating in viscous media. Studies were also performed in order to obtain c-axis oriented AlN films deposited directly on Si substrates at reduced temperatures. The deposition technique used was HiPIMS, and the results indicated significant improvements in the film texture when comparing to the conventional Pulsed DC deposition process.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2014. 83 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1160
Keyword
Aluminum nitride, reactive sputtering, c-axis oriented films, tilted films, electroacoustic devices, piezoelectric materials, Aluminum Scandium Nitride, HiPIMS, high-k dielectric
National Category
Other Materials Engineering
Research subject
Engineering Science with specialization in Electronics
Identifiers
urn:nbn:se:uu:diva-229588 (URN)978-91-554-8995-3 (ISBN)
Public defence
2014-09-24, Conference Room, FEEC, UNICAMP, Av. Albert Einstein, 400 / Cidade Universitária Zeferino Vaz / Distrito Barão Geraldo, Campinas, Brazil, 14:30 (English)
Opponent
Supervisors
Available from: 2014-09-01 Created: 2014-08-11 Last updated: 2014-09-08

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Publisher's full texthttp://www.theiet.org/resources/journals/eletters/4903/filter-transform.cfm

Authority records BETA

Moreira, MilenaBjurström, JohanKatardjiev, IliaYantchev, Ventsislav

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