Design and simulation of a thermally actuated MEMS switch for microwave circuits

Abstract

The design, modeling, and optimization of a novel, thermally actuated CMOS-MEMS switch are presented in this article. This series capacitive MEMS switch solves the substrate loss and down-state capacitance degradation problems commonly plaguing MEMS switches. The switch uses finger structure for capacitive coupling. The vertical bending characteristic of bimorph cantilever beams under different temperatures is utilized to turn the switch on and off. A set of electrical, mechanical, and thermal models is established, and cross-domain electro-thermo-mechanical simulations are performed to optimize the design parameters of the switch. The fabrication of the switch is completely CMOS-process compatible. The design is fabricated using the AMI 0.6 μm CMOS process and a maskless reactive-ion etching process. The measured results show the insertion loss and isolation are 1.67 and 33 dB, respectively, at 5.4 GHz, and 0.36 and 23 dB at 10 GHz. The actuation voltage is 25 V and the power consumption is 480 mW. This switch has a vast number of applications in the RF/microwave field, such as configurable voltage control oscillators, filters, and configurable matching networks. © 2009 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009.