A transient SPICE model for dielectric-charging effects in RF MEMS capacitive switches

A transient simulation program with integrated circuit emphasis (SPICE) model for dielectric-charging effects in RF microelectromechanical system (MEMS) capacitive switches was developed and implemented in a popular microwave circuit simulator. In this implementation, the dielectric-charging effects are represented by R-C subcircuits with the subcircuit parameters extracted from directly measured charging and discharging currents in the picoampere range. The resulted model was used to simulate the actuation-voltage shift in switches due to repeated operation and dielectric charging. Agreement was obtained between the simulated and measured actuation-voltage shift under various control waveforms. For RF MEMS capacitive switches that fail mainly due to dielectric charging, the present SPICE model can be used to design control waveforms that can either prolong lifetime or accelerate failure.