A Squeeze Film Damping Model for a Torsion Micro-mirror with Coupling Effect Between Torsion and Bending

Abstract

The prediction of squeeze film damping is very significant in designing high Q MEMS devices. In the past, there have been many analytical models studying the squeeze film damping of torsion micro-mirrors. However, the previous models didn’t consider the coupling motion of torsion and bending. This paper presents an analytical model for squeeze film damping considering the coupling motion of torsion and bending. In this paper, the modified Reynolds equation is solved by using the double sine series and the pressure distribution in the gap is derived, then the squeeze film damping force and torque applied to the micro-plate are derived. By solving the coupled equations of torsion and bending, the expression of the quality factor of the model is obtained. The accuracy of the present model is verified by comparing its results with the finite element method(FEM) solutions. The limitations and conclusions of the model are presented at the final state.