Design and fabrication of rf mems switches and instrumentation for performance evaluation

Atasoy, Halil İbrahim
This thesis presents the RF and mechanical design of a metal-to-metal contact RF MEMS switch. Metal-to-metal contact RF MEMS switches are especially preferred in low frequency bands where capacitive switches suffer from isolation due to the limited reactance. Frequency band of operation of the designed switch is from DC to beyond X-band. Measured insertion loss of the structure is less than 0.2 dB, return loss is better than 30 dB, and isolation is better than 20 dB up to 20 GHz. Isolation is greater than 25 dB below 10 GHz. Hence, for wideband applications, this switch offers very low loss and high isolation. Time domain measurement is necessary for the investigation of the dynamic behavior of the devices, determination of the ‘pull in’ and ‘pull out’ voltages of the membranes, switching time and power handling of the devices. Also, failure and degradation of the switches can be monitored using the time domain setup. For these purposes a time domain setup is constructed. Moreover, failure mechanisms of the RF MEMS devices are investigated and a power electronic circuitry is constructed for the biasing of RF MEMS switches. Advantage of the biasing circuitry over the direct DC biasing is the multi-shape, high voltage output waveform capability. Lifetimes of the RF MEMS devices are investigated under different bias configurations. Finally, for measurement of complicated RF MEMS structures composed of large number of switches, a bias waveform distribution network is constructed where conventional systems are not adequate because of the high voltage levels. By this way, the necessary instrumentation is completed for controlling a large scale RF MEMS system.


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This thesis reports the development of advanced readout and control electronics for MEMS gyroscopes developed at METU. These gyroscope electronics are separated into three main groups: high sensitive interface circuits, drive mode amplitude controlled self oscillation loops, and sense mode phase sensitive amplitude demodulators. The proposed circuits are first implemented with discrete components, and then integrated on CMOS chips. A self oscillation loop enabling constant amplitude drive mode vibrations in...
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Çetintepe, Çağrı; Demir, Şimşek; Department of Electrical and Electronics Engineering (2010)
This thesis presents development of microwave lumped elements for a specific surface-micromachining based technology, a self-contained mechanical characterization of fixed-fixed type beams and realization of a shunt, capacitive-contact RF MEMS switch for millimeter-wave applications. Interdigital capacitor, planar spiral inductor and microstrip patch lumped elements developed in this thesis are tailored for a surface-micromachining technology incorporating a single metallization layer, which allows an easy ...
Novel impedance tuner, phase shifter, and vector modulators using rf mems technology
Ünlü, Mehmet; Demir, Şimşek; Department of Electrical and Electronics Engineering (2009)
This thesis presents the theory, design, fabrication, and measurement results of novel reconfigurable impedance tuner, phase shifter, and vector modulators using the RF MEMS technology. The presented circuits are based on triple stub topology, and it is shown both theoretically and experimentally in this thesis that it is possible to control the insertion phase and amplitude of the input signal simultaneously using this topology. The presented circuits are implemented using an in-house, surface micromachini...
Tunable frequency microstrip antennas by rf-mems technology
Erdil, Emre; Aydın Çivi, Hatice Özlem; Department of Electrical and Electronics Engineering (2005)
This thesis presents the design, fabrication, and measurement of tunable frequency microstrip antennas using RF MEMS (Microelectromechanical Systems) technology. The integration of RF MEMS components with radiators enable to implement tunable systems due to the adjustable characteristics of RF MEMS components. In the frame of this thesis, different types of structures have been investigated and designed. The first structure consists of a microstrip patch antenna which is loaded with a microstrip stub whose ...
Performance evaluation of magnetic flux density based magnetic resonance electrical impedance tomography reconstruction algorithms
Eker, Gökhan; Eyüboğlu, Behçet Murat; Department of Electrical and Electronics Engineering (2009)
Magnetic Resonance Electrical Impedance Tomography (MREIT) reconstructs images of electrical conductivity distribution based on magnetic flux density (B) measurements. Magnetic flux density is generated by an externally applied current on the object and measured by a Magnetic Resonance Imaging (MRI) scanner. With the measured data and peripheral voltage measurements, the conductivity distribution of the object can be reconstructed. There are two types of reconstruction algorithms. First type uses current de...
Citation Formats
H. İ. Atasoy, “Design and fabrication of rf mems switches and instrumentation for performance evaluation,” M.S. - Master of Science, Middle East Technical University, 2007.