부산대학교 도서관

Theoretical and graphical analysis of pull-in-voltage and figure of merit for a fixed-fixed capacitive MicroElectromechanical Systems (MEMS) switch is presented in this paper. MEMS switch consists of a thin electrodecalled bridge suspended over a central line and both ends of the bridge are fixed at the ground planes of a coplanarwaveguide (CPW) structure. A thin layer of dielectric material is deposited between the bridge and centre conductorto avoid stiction and provide low impedance path between the electrodes. When an actuation voltage is appliedbetween the electrodes, the metal bridge acquires pull in effect as it crosses one third of distance between them. Inthis study, we describe behavior of pull-in voltage and figure of merit (or capacitance ratio) of capacitive MEMS switchfor five different dielectric materials. The effects of dielectric thicknesses are also considered to calculate the valuesof pull-in-voltage and capacitance ratio. This work shows that a reduced pull-in-voltage with increase in capacitanceratio can be achieved by using dielectric material of high dielectric constant above the central line of CPW.