A Pull-in Model for Parallel-Plate Electrostatically MEMS Actuators with the Fringing Field Effect

Predicting Pull-in parameters is crucial in the design of MEMS actuators.In the past,the Pull-in parameters of parallel plate MEMS devices with the fringing field effect are often estimated by using finite element method(FEM).However,FEM is cumbersome,time consuming and non-transparent,which is not convenient for the design optimization.Usually,there are a simple analytical model and a detailed analytical model for fringing capacitance respectively.This paper uses the two models to derive the Pull-in model of parallel plate MEMS devices with the fringing field effect respectively.The accuracy of the two Pull-in models is examined by comparing their results with the FEM results.Simulation results show that the Pull-in model based on the simple analytical model for fringing capacitance is unsuitable to predict Pull-in parameters.The Pull-in model based on the detailed analytical model has shown a good agreement with the FEM results for a wide range of gap spacing.