An electrostatic repulsive-force based micro actuator for capacitive RF MEMS switch

A novel electrostatic repulsive force based micro actuator was firstly proposed to drive the capacitive radio frequency (RF) micro-electromechanical (MEMS) switch. The charging effects, which normally take place in the traditional electrostatic attractive force based MEMS switches, can be theoretically mitigated by using the proposed micro actuator, where no electric field will be produced across the dielectric when the proposed structure is actuated by the electrostatic repulsive force. The analytical models related to dielectric charging respectively derived from the electrostatic repulsive force and the electrostatic attractive force were analyzed and compared. In order to optimize the proposed micro actuator for further switch design, the formation mechanism and the operating principle of the electrostatic repulsive force was firstly analyzed, and then the relationships between displacement of movable electrode and the applied voltage were investigated by using the COMSOL Multiphysics software with the different micro actuator structures. The simulation results show that the maximum displacements of three new structures are bigger than the basic structure.