Design and Analysis of RF MEMS Shunt Capacitive Switch for Low Actuation Voltage & High Capacitance Ratio

Abstract

This paper presents the study of Radio-Frequency Micro-Electro Mechanical (RF MEMS) switches and is inspired by their superior performance over the contemporary solid-state devices (MESFET, PIN diode etc.) and their excellent performance in the field of communications for the past decade. The study focuses on the realization of electrostatically actuated capacitive shunt switches with the main emphasis being on low actuation voltage (or pull-down voltage) and high capacitance ratio of the switch. The beam used is meander based for low-spring constant and is suspended over a coplanar waveguide (CPW) transmission line. Low actuation voltage is achieved in the range of 2–6 V with a down-state capacitance of 5.53 pF and a reasonably high capacitance ratio of 117. The insertion loss (S21) of the switches is less than 0.75 dB in the ON-state. During the OFF-state, the switches have isolation higher than 40 dB from 10–20 GHz. A Switching time of 11.47 μs was achieved.