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摘要

"Utility of RF MEMS Miniature Switched Capacitors in Phase Shifting Applications" Authors: Amrita Chakraborty, Ph.D. and Bhaskar Gupta, Ph.D.; amrita.chakraborty2@gmail.com. Abstract: This paper demonstrates research carried out toward development of switched capacitors having miniature dimensions. Such devices are based on the radio frequency micro electro mechanical systems (RF MEMS) technique, which has gained prominence in implementing a wide variety of microwave and millimeter devices. Switched capacitors with standard or conventional dimensions are prone to several limitations, which are addressed by scaling down the standard dimensions by 150 times (in terms of area requirement). Such switched capacitors are employed to develop phase shifters working in K-band (22GHz) frequency range to yield appreciable performance both in terms of electromechanical and RF characterizations. Such switched capacitors are utilized to develop phase shifters, which find immense applications in the design of phased array RADARs. Switched capacitors fabricated on 500um thick quartz substrates result in 30° phase shift (0.66 × 1mm in dimension) with associated minimum -0.18dB insertion loss and better than -21dB reflection coefficient at 22GHz frequency. Electromechanical characterization reports an actuation voltage of 14.6V, mechanical vibration frequency of 2.5MHz and a switching time of 620ns respectively. Demonstrations showing complete realization of 180° phase shifter (4 × lmm) employing a cascaded arrangement of six similar 30° unit cells are also included. (EU - International Journal of Electronics and Communications, vol. 75, May 2017, https://doi.org/10.1016/j.aeue.2017.03.011)