Design and Manufacturing of a 5-bit MEMS Phase Shifter at K-band

This work present the design, and manufacturing of a novel K-band 5-bit MEMS phase shifter for applications in reconfigurable antenna systems. A hybrid architecture based on both switched line and loaded line topologies has been adopted. The device has been manufactured in microstrip technology on 200 µm thick high resistivity silicon substrate by using the 8-masks FBK MEMS process. The phase shifter full wave simulations show excellent performance in the frequency band of interest 20.2-21.2 GHz. Return loss and insertion loss better than 17 dB and 2 dB and phase error minor than 2 degrees are obtained for all the 2^5 phase shifter states. The on-wafer measurements of the single bits confirmed such high performance, showing a phase error minor than 2.5 degrees and a return loss better tan 20 dB for all bits. The losses are dominated by the MEMS switch contact resistance, which is about 1.8 Ohm for every MEMS clamped-clamped beam ohmic switch. A low cost plastic package has been designed and manufactured as well. The on-wafer measurements of the complete 5-bit phase shifter are in progress as well as the packaged device.