RF MEMS Coplanar Shunt Switches Based on SU-8 Technology

RF MEMS switches are currently considered for isolation and transmission of RF signals as the ideal next generation devices with respect to PIN diodes, because of the very low losses, high reliability, no signal distortion and no power consumption. In this work, RF MEMS shunt switches in coplanar waveguide (CPW) configuration have been designed, realized and tested for wideband isolation purposes. SU-8 negative resist technology has been introduced for improving the bridge mechanics and the RF performances of the device. The polymeric material is used to elevate the ground planes of the CPW structure, with minor consequences on the electrical matching and an improvement in the bridge ends definition. The EM design has been followed by a six-step photo-lithographic process on a 4" oxidized high resistivity silicon wafer, up to the release of the bridge by using a plasma etching technique.