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Bjurström, Johan
Publications (10 of 27) Show all publications
Moreira, M., Bjurström, J., Katardjiev, I. & Yantchev, V. (2013). Efficient RF voltage transformer with bandpass filter characteristics. Electronics Letters, 49(3), 198-199
Open this publication in new window or tab >>Efficient RF voltage transformer with bandpass filter characteristics
2013 (English)In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 49, no 3, p. 198-199Article 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
Keywords
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:nbn:se:uu:diva-185262 (URN)10.1049/el.2012.3982 (DOI)000318542500023 ()
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
Moreira, M. & Bjurström, J. (2012). Synthesis and characterization of highly c-textured Al(1-x)ScxN. In: Materials Research Society. Paper presented at Materials Research Society.
Open this publication in new window or tab >>Synthesis and characterization of highly c-textured Al(1-x)ScxN
2012 (English)In: Materials Research Society, 2012Conference paper, Oral presentation only (Refereed)
National Category
Engineering and Technology
Research subject
Engineering Science with specialization in Electronics
Identifiers
urn:nbn:se:uu:diva-185260 (URN)
Conference
Materials Research Society
Available from: 2012-11-21 Created: 2012-11-21 Last updated: 2013-01-02
Moreira, M. D., Bjurström, J., Yantchev, V. & Katardjiev, I. (2012). Synthesis and characterization of highly c-textured Al(1-x)Sc(x)N thin films in view of telecom applications. In: More than moore: Novel materials approaches for functionalized silicon based microelectronics. Paper presented at Symposium M on More than Moore - Novel Materials Approaches for Functionalized Silicon Based Microelectronics at Spring Meeting of the European-Materials-Research-Society (E-MRS); 14-18 May 2012; Strasbourg, FRANCE (pp. 012014).
Open this publication in new window or tab >>Synthesis and characterization of highly c-textured Al(1-x)Sc(x)N thin films in view of telecom applications
2012 (English)In: More than moore: Novel materials approaches for functionalized silicon based microelectronics, 2012, p. 012014-Conference paper, Published paper (Refereed)
Abstract [en]

Wurtzite AlN is a piezoelectric material with excellent electro-acoustic properties and is used for the fabrication of high frequency thin film micro-acoustic components, most notably filters, duplexers, resonators, etc. Its moderate electromechanical coupling coefficient (k(t)(2)) of 6%-7% is insufficient for applications requiring larger bandwidths. Recent theoretical and experimental studies indicate that AlN alloyed with Sc exhibits a substantially higher piezoelectric constant than pure AlN. This study aims at determining the main electro-acoustic parameters of Al(1-x)Sc-(x) N in view of large bandwidth applications. To this end, highly c-textured Al(1-x)Sc(x) N thin films have been synthesized with relative Sc concentrations of up to 0,15. Subsequently, FBAR resonators were fabricated and characterized as a function of the Sc content. It is seen that k(t)(2) increases linearly with the latter to a value of 12% for a Sc concentration of x=0,15, while the Q value decreases from 739 to about 348 in the same concentration range. Likewise, the TCF varies from -35,9ppm/degrees C to -39,8ppm/degrees C, while the dielectric constant increases from epsilon=10 to a value of 14,1 for x=0,15. Finally, the relative dielectric losses are seen to increase by approximately a factor of two.

Series
IOP Conference Series-Materials Science and Engineering, ISSN 1757-8981 ; 41
National Category
Natural Sciences Engineering and Technology
Research subject
Engineering Science with specialization in Electronics
Identifiers
urn:nbn:se:uu:diva-192687 (URN)10.1088/1757-899X/41/1/012014 (DOI)000312412000014 ()
Conference
Symposium M on More than Moore - Novel Materials Approaches for Functionalized Silicon Based Microelectronics at Spring Meeting of the European-Materials-Research-Society (E-MRS); 14-18 May 2012; Strasbourg, FRANCE
Available from: 2013-01-25 Created: 2013-01-24 Last updated: 2013-03-04Bibliographically approved
Moreira, M. & Bjurström, J. (2012). Synthesis and characterization of wurtzite Al(1-x)ScxN thin films. In: International Symposium on Ultrasonics, ferroelectrics and frequency control. Paper presented at International Symposium on Ultrasonics, ferroelectrics and frequency control.
Open this publication in new window or tab >>Synthesis and characterization of wurtzite Al(1-x)ScxN thin films
2012 (English)In: International Symposium on Ultrasonics, ferroelectrics and frequency control, 2012Conference paper, Poster (with or without abstract) (Refereed)
National Category
Engineering and Technology
Research subject
Engineering Science with specialization in Electronics
Identifiers
urn:nbn:se:uu:diva-185258 (URN)
Conference
International Symposium on Ultrasonics, ferroelectrics and frequency control
Available from: 2012-11-21 Created: 2012-11-21 Last updated: 2013-01-02
Moreira, M., Bjurström, J., Kubart, T., Kuzavas, B. & Katardjiev, I. (2011). Synthesis of c-tilted AlN films with a good tilt and thickness uniformity. In: Proceedings of IEEE INTERNATIONAL ULTRASONICS SYMPOSIUM: . Paper presented at IEEE INTERNATIONAL ULTRASONICS SYMPOSIUM (IUS), 18-21 October, 2011, Orlando, FL, USA (pp. 1238-1241). New York, USA
Open this publication in new window or tab >>Synthesis of c-tilted AlN films with a good tilt and thickness uniformity
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2011 (English)In: Proceedings of IEEE INTERNATIONAL ULTRASONICS SYMPOSIUM, New York, USA, 2011, p. 1238-1241Conference paper, Published paper (Refereed)
Abstract [en]

This communication describes a method for the deposition of thin piezoelectric AlN films with an inclined c-axis relative to the surface normal. Further, the tilt over the wafer is sufficiently uniform and exhibits a planar symmetry as well as good thickness uniformity. Careful control of both the nucleation and growth stages is needed to obtain tilted films with excellent quality. Thus in the nucleation state, it is argued that two independent mechanisms, namely seed layer texture and/or surface roughness, are mainly responsible for the subsequent titled growth. To achieve the latter, however, a certain directionality of the deposition flux is also necessary. The directionality of the deposition flux is achieved through the use of an array of linear magnetrons tilted under a certain angle with respect to the substrate normal.

Place, publisher, year, edition, pages
New York, USA: , 2011
Keywords
AlN, c-axis tilt, piezoelectric, shear waves
National Category
Other Materials Engineering
Identifiers
urn:nbn:se:uu:diva-189952 (URN)000309918400287 ()978-1-4577-1252-4 (ISBN)
Conference
IEEE INTERNATIONAL ULTRASONICS SYMPOSIUM (IUS), 18-21 October, 2011, Orlando, FL, USA
Projects
WISENET
Funder
Vinnova
Available from: 2013-01-05 Created: 2013-01-05 Last updated: 2015-01-07
Sharma, G., Liljeholm, L., Enlund, J., Bjurström, J., Katardjiev, I. & Hjort, K. (2010). Fabrication and characterization of a shear mode AlN solidly mounted resonator-silicone microfluidic system for in-liquid applications. Sensors and Actuators A-Physical, 159(1), 111-116
Open this publication in new window or tab >>Fabrication and characterization of a shear mode AlN solidly mounted resonator-silicone microfluidic system for in-liquid applications
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2010 (English)In: Sensors and Actuators A-Physical, ISSN 0924-4247, E-ISSN 1873-3069, Vol. 159, no 1, p. 111-116Article in journal (Refereed) Published
Abstract [en]

A shear mode AlN solidly mounted resonator (SMR) microfluidic sensor system was fabricated and characterized. The AlN SMR fabrication process is fully IC compatible and uses reactive sputtering to deposit piezoelectric AlN thin films with a non-zero mean inclination of the c-axis, which allows in-liquid operation through the excitation of the shear mode. Silicone encapsulation bonded on top of the Si sensor chip includes a microfluidic system to transport the analyte and confine the flow to the active area of the sensor chip. The sensor operation in air, water, glycerol and acetone was characterized. The resonator had a resonance frequency of around 1.2 GHz and a Q value in water of around 100. Results concerning the stability and resolution are also presented. The results indicate a potential of highly sensitive low-cost microfluidic sensor systems for applications in, e.g. point-of-care testing.

Keywords
surface mounted resonator, pdms, microfluidic system
National Category
Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-100394 (URN)10.1016/j.sna.2010.02.009 (DOI)000277661800016 ()
Projects
WISENET
Available from: 2009-03-31 Created: 2009-03-31 Last updated: 2017-12-13Bibliographically approved
Wingqvist, G., Yantchev, V., Bjurström, J. & Katardjiev, I. (2008). Thin film bulk acoustic resonators (FBARs) for biosensor applications. In: : . Paper presented at 7th International Workshop on Micromachined Ultrasonic Transducers, Trondheim, May 8-9.
Open this publication in new window or tab >>Thin film bulk acoustic resonators (FBARs) for biosensor applications
2008 (English)Conference paper, Published paper (Refereed)
National Category
Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-111004 (URN)
Conference
7th International Workshop on Micromachined Ultrasonic Transducers, Trondheim, May 8-9
Projects
WISENET
Available from: 2009-12-01 Created: 2009-12-01 Last updated: 2018-06-26Bibliographically approved
Wingqvist, G., Bjurström, J., Hellgren, A.-C. & Katardjiev, I. (2007). Immunosensor utilizing a shear mode thin film bulk acoustic sensor. Sensors and actuators. B, Chemical, 127(1), 248-252
Open this publication in new window or tab >>Immunosensor utilizing a shear mode thin film bulk acoustic sensor
2007 (English)In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 127, no 1, p. 248-252Article in journal (Refereed) Published
Abstract [en]

An AlN thin film electro-acoustic resonator has been fabricated employing a reactive sputtering process for the deposition of an AlN thin film with inclined c-axis for excitation of the shear mode for operation in liquid media. The main objective is to investigate the efficiency of the micro-fluidic channel system integrated in the silicon wafer underneath the AlN resonator. A comparative study between the shear mode thin film bulk acoustic resonator (FBAR) and a quartz crystal microbalance (QCM) using a competitive antibody–antigen association process for detection of drug molecules is presented.

Keywords
Competitive immunosensor, Shear mode FBAR, Drug detection
National Category
Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-11757 (URN)10.1016/j.snb.2007.07.051 (DOI)000250691100039 ()
Available from: 2007-10-16 Created: 2007-10-16 Last updated: 2017-12-11Bibliographically approved
Wingqvist, G., Bjurström, J., Liljeholm, L., Yantchev, V. & Katardjiev, I. (2007). Shear mode AlN thin film electro-acoustic resonant sensor operation in viscous media. Sensors and actuators. B, Chemical, 123(1), 466-473
Open this publication in new window or tab >>Shear mode AlN thin film electro-acoustic resonant sensor operation in viscous media
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2007 (English)In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 123, no 1, p. 466-473Article in journal (Refereed) Published
Abstract [en]

A shear mode thin film bulk acoustic resonator (FBAR) operating in liquid media together with a microfluidic transport system is presented. The resonator has been fabricated utilizing a recently developed reactive sputter-deposition process for AlN thin films with inclined c-axis relative to the surface normal with a mean tilt of around 30°. The resonator has a resonance frequency of around 1.2 GHz and a Q value in water of around 150. Sensor operation in water and glycerol solutions is characterized. Theoretical analysis of the sensor operation under viscous load as well as of the sensitivity and stability in general is presented. The theoretical predictions are compared with experimental measurements. The results demonstrate clearly the potential of FBAR biosensors for the fabrication of highly sensitive low cost biosensors, bioanalytical tools as well as for liquid sensing in general.

Keywords
AlN, Biosensor, FBAR, Quasi-shear polarized acoustic wave, Thickness mode resonator, Tilted films
National Category
Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-10554 (URN)10.1016/j.snb.2006.09.028 (DOI)000246171200068 ()
Projects
WISENET
Available from: 2007-04-04 Created: 2007-04-04 Last updated: 2017-12-11Bibliographically approved
Bjurström, J., Lidbaum, H., Wingqvist, G., Katardjiev, I. & Leifer, K. (2007). Synthesis of highly textured thin piezoelectric AlN films with a tilted c-axis. In: : . Paper presented at 17th International Vacuum Conference (IVC-17), 13th International Conference on Surface science (ICSS-13), International Conference on Nanoscience and Technology 2007 (ICN+T 2007) Stockholm, Sweden, 2-6 June.
Open this publication in new window or tab >>Synthesis of highly textured thin piezoelectric AlN films with a tilted c-axis
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2007 (English)Conference paper, Published paper (Refereed)
National Category
Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-12726 (URN)
Conference
17th International Vacuum Conference (IVC-17), 13th International Conference on Surface science (ICSS-13), International Conference on Nanoscience and Technology 2007 (ICN+T 2007) Stockholm, Sweden, 2-6 June
Projects
WISENET
Available from: 2008-01-11 Created: 2008-01-11 Last updated: 2019-04-24Bibliographically approved
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