A Novel High Capacitance Ratio RF MEMS Switch with Low Pull-in Voltage

An RF MEMS capacitive switch, which has a high capacitance ratio and low pull-in voltage, is designed and analyzed in this paper. The switch can change the switch’s up and down state (on and off state) capacitance by adding an H-shaped floating metal layer on the dielectric layer, which dramatically improves the capacitance ratio of the switch without changing the switch’s material and structure. The switch’s pull-in voltage is reduced by bending the spring beam to lower the switch spring coefficient. Finally, through theoretical analysis and finite element simulation, the obtained pull-in voltage is 4.7 V. When the switch is working at 33 GHz, the isolation is −60 dB, the insertion loss is −0.42 dB, and the capacitance ratio is 301. The switch shows good performance.