Beam and dielectric materials impact on improvement of the performance of a novel capacitive shunt RF MEMS switch

Abstract

This paper presents a novel radiofrequency micro‐electro‐mechanical systems (RF MEMS) shunt capacitive switch having high isolation and low insertion loss for microphone applications. The device optimization and various electromechanical analysis are performed using a finite element modeler (FEM) solver. The proposed switch results in a pull‐in voltage of 36.88 V to displace movable beam 2/3rd of its initial gap. By varying beam material, dielectric material, beam‐dielectric thickness, and air gap between movable beam and dielectric layer, various electromechanical and electromagnetic analyses are carried out. For better isolation, silicon nitride (Si3N4) is used for the dielectric layer than hafnium oxide (HfO2) and silicon carbide (SiC). To achieve maximum displacement of the beam, various materials such as aluminum, gold, nickel, and copper are chosen; among all, this gold shows high displacement because of its good conductivity. By implementing various meandering techniques along with perforations, pull‐in voltage and stiction problems are reduced. The switch exhibits good return loss of −28 dB and insertion loss of −0.017 dB during on‐state at 5 GHz and high isolation of −41.26 dB at 10.5 GHz during off‐state. The proposed switch is used at the subsystem/device level in the future microphone, aircraft navigation, and satellite applications.