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 Micro-Electro-Mechanical-Systems (MEMS) phase shifters based on similar architectures (combination of switched line and loaded line) but employing different MEMS switch typologies (cantilevers and air bridges) and RF junctions (SP2T and SP4T). All devices have been monolithically manufactured on 200 mm thick high resistivity silicon substrate (4′′) by using the Fondazione Bruno Kessler (FBK) RF MEMS process. The performance of the different devices has been compared in order to identify the best configuration to be implemented in electronically steerable phased array antennas for satellite COTM (communication on the move) terminals. Excellent performances were measured for the dielectric-free pad RF MEMS switches as well as the single bits constituting the phase shifter. The three 5-bit devices show return losses 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, SP4 T-based design. A low-cost Surface Mountable Technology (SMT) one-level package has been developed as well to allow the phase shifter integration into phased array antennas by using automatic surface mounting techniques. The design and simulation of the SMT package are also presented together with its measured RF performance.