Finite Element Analysis of Squeezed Film Damping on Trapezoidal Microcantilever Resonators at Different Pressure Levels

Squeezed film damping (SFD) becomes a dominant damping mechanism in micro-electro-mechanical system (MEMS). Depending on the pressure variation in MEMS, SFD governs the dynamic parameters like quality factors (Q factors) and damping ratio. In the present paper, we calculate the Q factor and damping ratio of the trapezoidal shaped microcantilever beam by eigenfrequency analysis using finite element method (FEM) in COMSOL Multiphysics. The effective viscosity method is used to calculate the SFD in FEM for the continuum, slip, transition and molecular flow regimes as described by the Knudsen no. (K_n). K_n is varied by altering the operating pressure, keeping the thickness of air gap constant. It is observed that the Q factor and damping ratio of trapezoidal microcantilever beam varies by an order of million for different flow regimes with the change of operating pressure from atmospheric to 0.1 Pa.