Analysis of electromagnetic interference of a capacitive RF MEMS switch during switching

Based on the dynamic model of the membrane bridge for a capacitive RF MEMS switch, the switching process may be divided into four stages: the charging of the switch capacitor, pull-down of the bridge, discharging of the switch capacitor, and the release of the bridge. A model for the electromagnetic field produced in each stage is developed by using Maxwell equations. In the charging stage and the discharging stage, the value of the magnetic field produced is invariable (6, 20.7 A/m) and the electric field increases or decreases linearly. But in the pull-down stage the electromagnetic field produced is a pulse field (maximum value is 6.05 A/m). In the release stage, the magnitude of the electromagnetic field is too small to be considered. The electromagnetic field will induce noise on the RF signal in the CPW during switching. Finally, the electromagnetic field model is verified by numerical simulations. The electromagnetic field model and analysis presented here are valuable to optimize the design in order to minimize the electromagnetic interference.