Monolithic integration of passive RF components by MEMS

A novel design of switched-line RF-MEMS (radio frequency micro electro mechanical systems) phase shifter for the X-Ku band (8 ~ 18 GHz) has been successfully developed by monolithically integrating electrostatic micro actuation mechanism of MEMS with a movable coplanar waveguide made of single crystalline silicon. MEMS and RF designs have been performed with minimum geometrical conflicts thanks to the layer-wise functional allocation method, where double surfaces of SOI (silicon on insulator) wafer are used. We have successfully demonstrated the design principle on a 1-bit phase shifter of 22.5 degrees at 12 ~ 13 GHz and obtained insertion loss of 1.6 ~ 18 dB/bit, return loss of -9 ~ 12 dB, and isolation of -52 ~ -55 dB by the electrostatic operation under 40 V.