Design and Simulation of Radio Frequency Micro Electro Mechanical Capacitive Shunt Switches

Radio Frequency Micro ElectroMechanical (RFMEM) switches play an important role in microwave switching. The demand for low voltage, low insertion loss, high Isolation RF MEMS capacitive switches for high frequency (10-40 GHz) applications has led to the development of MEMS based switching devices in the RF domain. This work reports the design and simulation of RF MEMS capacitive shunt switches for K and Ka bands. The switching element consists of a thin gold membrane which gets actuated over a transmission line under an applied bias. The dc simulation is carried out in CoventorWare and the designed switch is found to actuate at 18.75 volts. HFSS simulation results demonstrate an acceptable RF performance with an insertion loss of 0.25 dB in the range 20-35 GHz and an isolation better than 20 dB beyond 20 GHz.