Electromechanical Analysis of a Micromachined Comb-Drive Actuator by Admittance Measurement

Abstract

Electromechanical analysis of a micromachined comb-drive actuator based on equivalent circuit method is described. From the equivalent circuit, we formulated electrical admittance for a comb-drive actuator as a function of AC driving frequency and derived some relation between specific frequencies which can be obtained by admittance measurement. We have also found that mechanical parameters of a comb-drive actuator such as spring constant, rigid mass and mechanical resistance could be estimated by the relation of the specific frequencies. Using this theory we evaluated mechanical properties of a fabricated comb-drive actuator and confirmed its practical usefulness for characterization of a comb-drive actuator.