Design and simulation of capacitive SPDT RF MEMS switch to improve its isolation

This paper presents the simulation and analysis of capacitive shunt SPDT RF MEMS switch for high radio frequency applications. The design is based on the shunt configuration consisting of 2 capacitive type switches. To reduce pull in voltage, the high-frequency capacitive SPDT switch is proposed. The beam is designed with non-uniform meanders with perforations. By using the COMSOL Multiphysics tool, we found the pull-in voltage as 1.5 V at a beam thickness of 0.5 mu m. The corresponding capacitance ratio is 44 for the dielectric of Silicon Nitrate. The up sate and downstate capacitance of the switch is calculated and simulated. The performance analysis is done by using HFSS tool and is found to RF-perform excellently at 28 GHz with isolation of - 68 dB, the return and insertion losses are - 61 dB and - 0.1 dB respectively.