Fluidmechanical damping analysis of resonant micromirrors with out-of-plane comb drive

Damping is the liminting factor for the reachable maximum deflection. Thus, it is a very important issue for resonant microsystems. In this paper, we present a damping model for out-of-plane comb driven resonant micromirrors. The basic concept of this model is to attribute viscous damping in the comb gaps as the dominant contributor of damping moments. The model is extended by findings from a fluid-mechanical FEM model of an electrode finger and the moving mirror plate with a cavity underneath. It also considers effects from pressure and temperature changes. The results are verified and discussed in the context of experimental data. The primary goal of damping analysis and optimization is to minimize power consumption and to reduce driving voltage. The presented methods and models create the prerequisities for this task.