Integrated modeling of nonlinear dynamics and contact mechanics of electrostatically actuated RF-MEMS switches

In this work, a novel nonlinear dynamic model is developed to investigate the bouncing and deformation behaviors of an electrostatically actuated, ohmic-contact RF-MEMS switch. The model accounts for a real geometry, the electrostatic actuation, squeeze-film damping effect, and the nonlinear elastic-plastic contact mechanics using Hertz theory. A low-complexity formulation based on finite differential analysis is employed to solve the model equations in the time-domain. The proposed methodology is validated using a real four-contact RF-MEMS switch with complex geometry. The simulation results of the switch performance in the on-stage (closure) are in good agreement with experimental measurements demonstrating that the model is very effective in capturing the bouncing and contact deformation phenomena accurately. It is foreseen that the proposed approach will be instrumental in providing a better insight into the reliability of MEMS switches and will, ultimately, found a basis of developing and implementing control strategies to maximize their lifetime.