A 12GHz bulk-micromachined RF-MEMS phase shifter by SOI layer-separation design

Abstract

A novel design of monolithic RF-MEMS (radio frequency micro electro mechanical systems) phase shifter for Ku-band has been successfully developed based on a mechanically movable switched-line waveguide. The structures of MEMS actuators, switch contacts, and MEMS coplanar waveguides have been optimized in terms of insertion loss by utilizing the both sides of an SOI (silicon on insulator) wafer and by using the SOI layer-separation technique, where microwave waveguides and actuators are allocated on the handle wafer and the active layer of SOI, respectively. RF performance was measured on a developed 1-bit MEMS phase shifter, and we obtained insertion loss of −1.64 to −1.82 dB/bit, return loss of −8.92 to −12.60 dB/bit, and isolation of −40.29 dB/bit at 12.5 GHz. Phase-error for the 22.5-degree phase shifter was found to be 5.5 degree/bit at 12.5 GHz.