Design of Novel Low Actuation Voltage Shunt Capacitive RF MEMS Switch

Abstract

Wireless communication has witnessed rapid developments over the past few years. The highly compact RF circuits, invokes the benefits of miniaturized size, high performance, low weight and low cost for emerging personal and ground communications systems. Currently, RF MEMS are replacing the conventional microwave devices in various wireless transceiver applications. Switches, couplers and power dividers, high quality factor capacitors and inductors, resonant structures, etc. are some of the emerging RF MEMS devices. These switches are frequently used for mode selection, antenna design, and in transmitters and receivers. They offer many advantages over conventional electrical switches consisting of GaAs or FET diodes, owing to properties like linearity, high power handling capability, minimal insertion loss, reliability, and high isolation rates. This paper presents the design and analysis of a novel shunt capacitive RF MEMS switch which works in the X-band frequency (8-12GHz). The design consists of a thin aluminium micro-mechanical bridge suspended over a thin layer of dielectric material deposited over the silicon substrate. The design, modelling and simulation are done using COMSOL Multi-physics 5.1. The switch designed possess a low actuation voltage of 3V, low pull-in voltage of 2. 28V, optimum capacitance ratio and a low switching time of 36$\mu$s which makes it suitable for various existing wireless communication applications.