Static and electromagnetic analysis of RF MEMS shunt capacitive switch

Abstract

This paper introspect the design of capacitive shunt RF MEMS switches for low pull-in voltage and high stability with necessary electromagnetic analysis using Agilent ADS Momentum tool. It focuses on the state-of-art in low pull-in voltage switch design using beam meandering technique. Detail analysis of beam deflection vs. applied voltage characteristics using CoventorWare MEMS plus software for uniform one meander, uniform two meander, non-uniform one meander and serpentine meander is performed and it shows that serpentine meandered beam design has least pull-in voltage of 2.3V. In this paper different meander based switches are tested for stability by performing stress analysis using CoventorWare. Stress analysis shows that serpentine meandered switch experiences maximum stress of 2.9 MPa which is least among the considered switches and thus it can operate more no. of cycles before breakdown. S parameter analysis of all the structures is carried out to estimate the up state insertion loss, return loss and down state isolation. Comparative analysis between these parameters is done and effect of different geometry on insertion loss, return loss and isolation is also investigated. Extraction of parameters like upstate capacitance, downstate capacitance, bridge inductance, bridge resistance for serpentine, double uniform meanders and single non uniform meander structures are reported in this paper.