考虑边缘效应的平行平板式静电微执行器Pull-in模型

摘要

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.%在MEMS执行器的设计中，求出准确的Pull-in参数是至关重要的。在过去的研究中，对于漏电场不能忽略的平行平板式静电微执行器，通常只能采用有限元法数值求解。但是，有限元法繁琐、费时而且不直观。平行平板电容器的漏电容解析模型通常有两种：一种简单的；一种详细的。基于这两种漏电容解析模型，分别导出了漏电场不能忽略的平行平板式微执行器的Pull-in失稳方程,并将求解结果与ANSYS耦合场分析结果做了对比。结果表明，基于详细漏电容模型的结果精度良好，而且相对误差不随着极板间距的增大而增大。基于简单漏电容模型的结果精度太低，尤其在极板间距较大时。