Tunable frequency microstrip antennas by rf-mems technology

Erdil, Emre
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 length is controlled by RF MEMS switches. In the other structure, the length of a microstrip patch antenna is changed by connecting a metal plate using RF MEMS switches. The third structure is composed of a microstrip patch antenna and a microstrip stub on which RF MEMS variable capacitors are placed periodically to control the resonant frequency. In order to maintain an easier integration with RF MEMS capacitors, another structure consisting of a microstrip patch antenna and a coplanar waveguide (CPW) stub which is loaded with variable RF MEMS capacitors is designed. The final structure is a dual frequency CPW-fed rectangular slot antenna whose resonant frequencies are shifted by RF MEMS variable capacitors placed on a short circuited stub inserted inwards the antenna. The fabrication of CPW-fed rectangular slot antenna is completed in the MEMS fabrication facilities of METU using RF MEMS process based on electroforming on glass substrate. The measurement results show that RF MEMS components might be a proper solution to obtain tunable frequency antenna structures.


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...
Design and realization of broadband instantaneous frequency discriminator
Pamuk, Gökhan; Yıldırım, Nevzat; Department of Electrical and Electronics Engineering (2010)
n this thesis, RF sections of a multi tier instantaneous frequency measurement (IFM) receiver which can operate in 2 – 18 GHz frequency band is designed, simulated and partially realized. The designed structure uses one coarse tier, three medium tiers and one fine tier for frequency discrimination. A novel reflective phase shifting technique is developed which enables the design of very wideband phase shifters using stepped cascaded transmission lines. Compared to the classical phase shifters using coupled ...
HMIC miniaturization techniques and application on an FMCW range sensor transceiver
Korkmaz, Hakan; Demir, Şimşek; Department of Electrical and Electronics Engineering (2010)
This thesis includes the study of hybrid microwave integrated circuits (HMIC), miniaturization techniques applied on HMICs and its application on a frequency modulated continuous wave (FMCW) range sensor transceiver. In the scope of study, hybrid and monolithic microwave integrated circuits (HMIC and MMIC) are introduced, advantages and disadvantages of these two types are discussed. Large size of HMICs is the main disadvantage especially for military and civil applications requiring miniature volumes. This...
Modelling and noise analysis of closed-loop capacitive sigma-delta mems accelerometer
Boğa, Biter; Külah, Haluk; Department of Electrical and Electronics Engineering (2009)
This thesis presents a detailed SIMULINK model for a conventional capacitive Σ-Δ accelerometer system consisting of a MEMS accelerometer, closed-loop readout electronics, and signal processing units (e.g. decimation filters). By using this model, it is possible to estimate the performance of the full accelerometer system including individual noise components, operation range, open loop sensitivity, scale factor, etc. The developed model has been verified through test results using a capacitive MEMS accelero...
Capacitive cmos readout circuits for high performance mems accelerometers
Kepenek, Reha; Külah, Haluk; Department of Electrical and Electronics Engineering (2008)
This thesis presents the development of high resolution, wide dynamic range sigma-delta type readout circuits for capacitive MEMS accelerometers. Designed readout circuit employs fully differential closed loop structure with digital output, achieving high oversampling ratio and high resolution. The simulations of the readout circuit together with the accelerometer sensor are performed using the models constructed in Cadence and Matlab Simulink environments. The simulations verified the stability and proper ...
Citation Formats
E. Erdil, “Tunable frequency microstrip antennas by rf-mems technology,” M.S. - Master of Science, Middle East Technical University, 2005.