High Isolation Single Pole Four Throw RF MEMS Switches for X band

This work presents low loss RF-MEMS Single Pole Four Throw (SP4T) switch for X band. The present work is inspired from the fact that electrostatically actuated RF MEMS switches have superior RF performance over the state-of-the-art solid-state switches. Since an optimized design for Single Pole Multi Throw (SPMT) switch is difficult to realize, this work proposes a new design to achieve low loss and high isolation. The idea is to realize a combination of SPST (Single-Pole-Single-Throw) series and shunt switching in each arm of the SP4T model. The actuation voltage, isolation and insertion losses are optimized. The electro-mechanical modeling of the proposed device is done in CoventorWare and electro-magnetic modeling in HFSS. The simulation of the proposed design shows an actuation voltage of 12 V for capacitive shunt configuration and 13.75 V for the lateral series switch. The insertion loss and isolation are better than 1 dB and -50 dB respectively in the X band. The excellent RF characteristics make the switches suitable as MEMS varactors for high frequency applications and in tunable MEMS filters and phaseshifters.