Development of different k-band MEMS phase shifter designs for satellite COTM terminals

This work presents the design, manufacturing and testing of three 5-bit K-band MEMS phase shifters based on similar architectures (combination of switched line and loaded line) but employing different MEMS switch typologies (cantilevers & air-bridges) and RF junctions (SP2T & SP4T). All devices have been monolithically manufactured on 200 μm thick high resistivity silicon substrate (4”) by using the FBK MEMS process. The performance of the different devices have been compared in order to identify the best configuration to be implemented in electronically steerable phased arrays antennas for satellite COTM (communication on the move) terminals. Excellent performances were measured for the dielectric-free pad MEMS switches as well as the single bits constituting the phase shifter. The three 5-bit devices show return loss better than 15 dB for all states, with average insertion loss of 3.5 dB for the clamped-clamped, SP2T-based design, 2.2 dB for the cantilever, SP2T-based device and 2.1 dB for the cantilever, SP4T-based design. The measurements of the packaged devices are on-going.