Low-Voltage and High-Reliability RF MEMS Switch with Combined Electrothermal and Electrostatic Actuation

In this paper, we report a novel laterally actuated Radio Frequency (RF) Microelectromechanical Systems (MEMS) switch, which is based on a combination of electrothermal actuation and electrostatic latching hold. The switch takes the advantages of both actuation mechanisms: large actuation force, low actuation voltage, and high reliability of the thermal actuation for initial movement; and low power consumption of the electrostatic actuation for holding the switch in position in ON state. The switch with an initial switch gap of 7 µm has an electrothermal actuation voltage of 7 V and an electrostatic holding voltage of 21 V. The switch achieves superior RF performances: the measured insertion loss is -0.73 dB at 6 GHz, whereas the isolation is -46 dB at 6 GHz. In addition, the switch shows high reliability and power handling capability: the switch can operate up to 10 million cycles without failure with 1 W power applied to its signal line.