Analysis of Pull-in-Voltage and Figure-of-Merit of Capacitive MEMS Switch

Abstract

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

Research Status and Development Trend of MEMS Switches: A Review

“…What is more, according to the contact modes, MEMS switches can be grouped into resistive switches and capacitive switches, a classification quite common seen in RF (radio frequency) MEMS applications. Capacitive switches are turned on or off through capacitance coupling [ 34 ], and these types of switches are suitable for high-frequency (about 3 MHz to 30 MHz) applications [ 35 , 36 ]. On the other hand, resistive switches are generally used in the lower frequency band (about 30 KHz to 300 KHz) of the radio frequency signal [ 37 ].…”

Review of microshutters for switchable glass

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