Equivalent Network Approach for the Simulation of MEMS Devices

In this paper a numerical approach for the analysis of the behaviour of micro electro mechanical systems (MEMS) is presented. The method is applied to the simulation of movable plate MEMS variable capacitors that are of common use in the CMOS voltage controlled oscillators (VCOs). An accurate study of MEMS devices requires a coupled electro-mechanical analysis. The mechanical analysis has to take into account the deformation of the plates of the capacitor and the electromagnetic one has to consider the distribution of charges and currents and the presence of dielectric materials. We first perform a coupled elastic-electrostatic analysis in order to obtain the tuning characteristic of the system; subsequently, once the positions of the plates have been determined, an electromagnetic analysis of the system is performed via an integral formulation based on an electric equivalent circuit. The proposed method has been validated by analysing two and three plate tuneable parallel-plate capacitors.