Performance Calculation for a MEMS Switch with a Floating Electrode

Abstract

Switches fabricated using MEMS technology are considered as a promising element base of radio electronics. The main characteristic of a MEMS switch is the ratio of capacitances in the closed and open states. For conventional devices, this ratio is of several units, but it can be significantly increased by implementing original design solutions. This paper studies the switch, which is a combination of capacitive and resistive devices. Its working characteristics are considered depending on the substrate properties and contact resistance. The switch provides a capacitance ratio of 27.7 and 46.1 when using sapphire and borosilicate glass substrates, while high-resistivity silicon does not allow attaining values above 7.4 due to the high parasitic capacitance. The isolation and insertion loss are 14.7–19.4 and 0.8–1.1 dB in the frequency range of 4–10 GHz on a sapphire wafer. Acceptable S-parameters are achieved when the contact resistance is not higher than 1 Ω.