Microwave Microsystems: Technology and Modelling of RF MEMS Switches and Related Applications

The aim of this contribution is to overview the technology, modeling and measurement techniques devoted to RF Micro-Electro-Mechanical Systems (MEMS) and related architectures based on micro-switches. In particular, the main aspects in optimizing the manufacturing yield will be stressed, together with the modeling issues. Actually, EM simulations as well as thermal, power handling and mechanical ones are always needed to have an accurate prediction before the fabrication. Software tools have been purposely developed to account for all of the above contributions and to state the reliability of such a technology. The characterization, far to be a standard measurement activity, because of the novelty of many effects related to RF micro-system devices, has to include combined solicitations to validate both the modelling and the manufacturing process. Single-Pole-DoubleThrow (SPDT) and Phase Shifters based on RF MEMS will be presented as a natural implementation of micro-systems utilizing the individual switches. Experimental results obtained for a binary distributed phase shifter based on RF MEMS coplanar shunt switches will be also presented. A new approach based on the image parameter representation of two-port networks is proposed for the modeling of this structure. Vector Network Analyzer measurements have been performed by recording the scattering parameters of the device, obtaining a differential phase shift of 180° at the frequency f theoretical one ftheo0= 13.7 GHz, very close to the fexp=14 GHz. A very low number of switches has been used for the realization of the component.