Circuital Modeling of Coplanar Series RF-MEMS Switches

There are two basic switches used in RF to mm-wave circuit design: the shunt switch and the series switch. The aim of our research activity was to perform calibrated measurements of some different types of MEMS series switches which were fabricated at Istituto Trentino di Cultura, Centro per la Ricerca Scientifica e Tecnologica (Trento-ITALY), and, after that, to extract the CLR (capacitance, inductance and resistance) model of the switch from S-parameter measurements. The results are very useful for designing microwave circuits witch use MEMS series switches. Therefore, in order to place the MEMS switches in the microwave circuits, it is very important to have simple and effective models to be implemented for simulation in CAD programs. The aim of this paper is to present some measurements results and to model a CLR equivalent circuit of a series-connected MEMS switch. A good agreement with experimental results confirms the validity of the proposed model.