Analysis of squeeze film air damping in MEMS with lattice Boltzmann method

Squeeze film air damping has significant impact on the performance of microelectromechanical devices. In order to understand the squeezed-film damping mechanism, Reynolds equation and its derivatives have been used in previous studies. In fact, the Reynolds equation has limitations in quantifying MEMS characteristics because its assumptions on small amplitude and non-slip boundary condition may not be satisfied in practice. Advanced modeling approaches should be considered to capture detailed energy dissipation physics. In this paper, we study the squeeze film air damping in MEMS using lattice Boltzmann method, which is derived from classical Boltzmann transport equation. Our major focus is to reveal how the air film is squeezed by the side movement of a comb structure. By considering the slippage and amplitude effect, direct lattice Boltzmann simulations are performed to obtain the Q factor. Viscous damping and elastic damping, two contributors to the energy loss, are quantitatively compared to reveal the dominant damping mechanism.