RF MEMS DMTL phase shifter on low-resistivity silicon for Ku band with reduced substrate loss

Distributed MEMS transmission line (DMTL) phase shifter on low resistivity silicon for Ku band is presented. The loss relating to the conductivity of silicon and carriers at the silicon-oxide interface is solved by completely removing the silicon as well as the oxide from underneath the CPW t-line. The only silicon left is to provide anchorage to movable sections of the CPW. This also results in a two movable plate system which simultaneously improves the actuation voltage and the switching speed. A phase shifter based on the two movable plate system is designed and a phase shift of 180° is obtained at Ku band with an insertion loss of 1.16dB for low resistivity silicon (10-20 Ωcm). A fabrication technique is proposed and initial fabrication results of the design are presented.