A methodology for fast finite element modeling of electrostatically actuated MEMS

In this paper, a methodology is proposed for expediting the coupled electro-mechanical finite element modeling of electrostatically actuated MEMS. The proposed methodology eliminates the need for repeated finite element meshing and subsequent electrostatic modeling of the device during mechanical deformation. We achieve this by using an approximation of the charge density on the movable electrode in the deformed geometry in terms of the charge density in the non-deformed geometry and displacements of the movable electrode. The electrostatic problem has to be solved only once and thus this method speeds up the coupled electro-mechanical simulation process. The proposed methodology is demonstrated through its application to the modeling of four MEMS devices with varying length-to-gap ratios, multiple dielectrics and complicated geometries. Its accuracy is assessed through comparisons of its results with results obtained using both analytical solutions and finite element solutions obtained using ANSYS. Copyright q 2008 John Wiley & Sons, Ltd.