Electromagnetic modelling of conductor-backed CPW based RF MEMS capacitive shunt switch

Abstract

This article will detail the creation of an electromagnetic model of an RF MEMS capacitive shunt switch using the conductor-backed CPW configuration. Full-wave S-parameter analysis has been carried out to extract the S-parameter of the switches for different variants. The modelling also covers the effect of the tapering of the RF signal line as well as the permittivity variation on the switch parameters. Further, the ground metallisation effect because of the CB-CPW configuration on the switch parameters has been modelled and compared with the standard topology. A scalable lumped circuit model for the proposed topology has been generated which can be easily incorporated in the circuit simulator. The topology demonstrated can achieve frequency downscaling without increasing the size and complexity of the circuit. Comparison of modelled and full wave simulated results shows good agreement.