Research • Research Areas

Microelectromechanical Systems

Silicon micromachining technology has become the predominant method in the fabrication of micron-sized electromechanical systems. MEMS devices have found applications in numerous areas, including RF device technology, chemical sensing, and ultrasonic imaging.

RF-MEMS: In order to diversify the services available to customers while remaining competitive, today's wireless communication systems must utilize technologies that enable faster performance and higher levels of integration but maintain lower cost. The post-processing of silicon wafers combined with MEMS design techniques can be used to create a variety of high-performance active and passive devices, reduce the number of off-chip components, as well as allow a more integrated solution without the need for expensive processes. The MEMS Group designs and fabricates RF MEMS devices such as varactors, RF-switches, micromachined inductors and resonators for use in transceiver architectures. Micromachined inductors are realized using an Above-IC process for a quality factor (Q) higher than 30.

Another area of interest is the design of MEMS based resonator filters to replace crystal or SAW intermediate frequency (IF) filter blocks in transceivers. Different types of resonator structures are studied based on their frequency response and IC compatibility for IF filter implementation. The Group also focuses on the realization of capacitive and contact RF switches for multiband transceiver blocks. Software tools such as COVENTOR, MEMSCAP, and ANSYS software tools are used in the optimization of device dimensions. A final area of research is the realization of multi-gap tunable capacitors to serve as LC tank elements in Voltage Controlled Oscillators or impedance matching elements in power amplifiers.

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Bio-Mems Chemical Sensors : The MEMS Group works on the design and implementation of a BioMEMS platform to quantify risk markers in human serum. Cardiovascular risk markers were chosen as a case study. The developed parallel analysis system uses a very small amount of serum and produces very fast, reliable results. Three different methodologies are assessed for optimal results: Optical, capacitive, and Quartz Crystal Microbalance (QCM).

Another field of interest is the realization of CMOS compatible chemical sensors using micromachining technology and aimed for the detection of gases such as oxygen, hydrogen, and hydrocarbons.

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Faculty: Yasar Gurbuz, Ayhan Bozkurt, Cem Ozturk

Recent Projects:

-- Development of Micromachined Chemical Sensors and Signal Read-out Circuitry, supported by the Scientific and Technological Research Council of Turkey (TUBITAK), 2001-2004.

-- Novel Protein Microchip Design for Biotechnology Applications, supported by TUBITAK, 2005-2007.

-- Biosensor/mems-based Protein Microchip Design; cardiovascular risk assessment platform, supported by the State Planning Organization of Turkey, 2005-2008.

-- MINAEAST-NET (Micro and Nano Technologies going to Eastern Europe through Networking), supported by EU 6th Framework, 2004-2006.

-- Design and Realization of an Intravascular Ultrasonic Imaging System, supported by TUBITAK, 2005-2010.

-- TARGET Top Amplifier Research Groups in a European Team, supported by EU 6th Framework, 2004-2008.

-- Realization of State-of-the-art IEEE802.11a, 15 (UWB) Transceiver Chipset and Compatible RF MEMS Components, supported by TUBITAK, 2005-2008.


Recent/Relevant Papers:

-- A lumped circuit model for the radiation impedance of a 2D CMUT array element, Bozkurt, A., Karaman, M., Proc. IEEE Ultrasonics Symposium, Rotterdam, Netherlands, 2005.

-- Polyurethane nanofiber webs for sensor and actuator applications, Demir, M., Naseer, M., Bechteler, T. F., Gurbuz, Y., Menceloglu, Y. Z. Proc. Microelectromechanical Systems (MEMS) MRS 2003 Fall Meeting, Boston, USA, December 1-3, 2003.

-- Electro-thermal simulations and modeling of micromachined gas sensors, Demirci T., Guney, D., Bozkurt, A., Gurbuz, Y., Proc. Microelectromechanical Systems (MEMS) Conference, Berkeley, California, USA, August 24-26, 2001.

-- Biosensor implementation for cardiovascular risk marker analysis, Gul, O., Inceturkmen, E, Kutuk, O, Basaga, H., Sezerman, U., Gurbuz, Y., Proc. IEEE, 31 Oct., 2005, pp. 303 - 305, 2005.

-- Diamond microelectronic gas sensor for detection of benzene and toluene, Gurbuz, Y., Kang, W. P., Davidson, J. L., Kerns, D. V., Sensors and Actuators B. Chemical, 99(2-3), 207-215, 2004.

-- An analytical design methodology for microelectromechanical (MEM) filters, Gurbuz, Y., Parlak, M., Bechteler, T.F., Bozkurt, A., Sensors and Actuators, A 119, 38-47, 2005.

-- Carbon-derived micro- and nanostructures for chemical sensing, Kang, W.P., Davidson, J. L., Wong, Y.M., Soh, K.L., Gurbuz, Y. (invited), Sensors, 2004, Proc. IEEE, 24-27 Oct. 2004, pp. 376 - 394, 2004.