Acoustic damping of a four-clamped membrane in ultrasonic microdevice

In this paper, we present an analytical model of the acoustic damping of a four-clamped membrane in a ultrasonic microelectromechanical system device. The model is used to analyze effects of acoustic damping on the dynamic behavior of the microdevice, in which four-clamped membranes vibrate at ultrasonic frequency, as well as a flow goes through the cavity under the membrane. A modified Reynolds equation that is derived from the Navier-Stokes equation is used to model the flow under the membrane. The analytical solutions for the damping pressure and force are obtained. Factors that affect the damping pressure and force are discussed. Furthermore, the result of the microdevicepsilas performance form analytical calculation is compared with that from the finite element method in ANSYS.