Simulations of Impulsive Dynamics in RF MEMS Capacitive Switches

Radio Frequency Micro-Electro-Mechanical Systems (RE MEMS) have emerged as a promising enabling technology for low-cost and low-power switches, actuators, and sensors. However, the reliability of these devices, especially those involving repeated contacting events, remains a major stumbling block for their widespread adaptation. In this work we present dynamic simulations of RE MEMS switch response due to electrostatic actuation in the presence of gas damping and residual stress. The dynamics emerging from the interaction between the beam structure and gas environment shows generation of stress waves induced by contact. It has been observed that these impulsive effects could lead to transient stresses that are significantly greater than the steady state bending stress. S-N curves for LIGA Nickel are used to make predictions for the lifetime at various voltages and operating gas pressures that show pressure dependence consistent with earlier experimental observations.