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 uni-dimensional approach based on analytical equations and a Finite Element Method (FEM) with commercial software simulations. The analytical model, developed by means of a MATHCAD program, has been used to predict the dynamics of the device, mainly taking into account its re-configuration time and the energy balance involved in the actuation and in the de-actuation mechanisms. After that, 2D and 3D simulations have been performed to get the really deformed shape of the bridge, depending on the central and lateral actuation of the suspended beam. After that, 2D and 3D simulations have been performed by a central and lateral actuation of the suspended beam to get the really deformed shape of the bridge. Theoretical and experimental results about the threshold voltage and the response time of the device confirm the validity of the proposed modeling.