Abstract
Attempts at predicting the squeeze film damping (SQFD) effects in MEMS devices have by and large been restricted to the following approaches; analytic [1] or numerical [3-5] modeling of the Reynolds equation, or numerical solutions of incompressible Navier-Stokes (NS) [6] and correcting the Reynolds or incompressible NS for the effects of high Knudsen number [3, 7]. There are key difficulties with these approaches that render them unsuitable or unacceptable for realistic design problems. Recently the development of a hybrid technique called Navier-Stokes-Reynolds (NSR) [8] has shown some promise in addressing some of the key difficulties in previous approaches. In this work we extend the method to a class of devices characterized by nonuniform gaps (e.g. tilting mirrors [2], accelerometers etc.). The micromachined high precision tunneling accelerometer designed at the SMSSL (Stanford University [9]) is one such device. A comparison of the experiments and predictions show quite good agreement over the operating regime of the device.