Abstract
This paper presents a design of a capacitive double beam MEMS microswitch based on dynamic pull-in actuation. The design consists of two suspended microbeams actuated by an electrostatic nonlinear force accounting for fringing field effect. The applied force controls the ON and the OFF states of the microswitch using a variable voltage. We first develop a mathematical model for the MEMS microswitch, then we investigate the static behavior and use finite element analysis to validate the derived mathematical model. A comparison with classical single beam design is also done. The results show 32% reduction in the actuation voltage when double beam design is used. Dynamic analysis using combination of DC and AC signals is examined, the outcome presents significant reduction in the actuation voltage. We demonstrate that driving the microswitch using square wave signals gives several improvements to the performance such as large pull-in band, low actuation voltage and small switching time. Global stability analysis showed that, for the same applied voltage, square wave signals are more efficient to actuate the microswitch. The electrostatic switching energy is also studied, we show that this energy can be optimized for specific switching times.