Mechanical modelling of capacitive RF MEMS shunt switches

The mechanical response of a RF MEMS shunt connected switch in coplanar waveguide configuration has been studied by using both an analytical approach based on uni-dimensional equations and FEM simulations. The analytical model has been developed for predicting the dynamics of the device, especially concerning its re-configuration time and the energy balance involved in the actuation and in the de-actuation mechanisms. The analytical evaluation was based on a MATHCAD program. After that, 2D and 3D simulations have been performed to get the deformed shape of the bridge, depending on the central and lateral actuation of the suspended beam. Theoretical and experimental results about the threshold voltage confirm the validity of the proposed modeling.