π-phase shifter using single RF MEMS SPDT switch

In this paper, a pi-phase shifter by using only single switch with simple network was proposed. By assembling one SPDT RF MEMS switch on a PCB substrate with two different electrical lengths, 1lambda_g and 1.5lambda_g at 9 GHz, of microstrip transmission lines, a 1-bit pi-phase shifter was implemented. The measured phase shifter exhibited 174deg phase shift at 9 GHz with phase variation less than plusmn 3deg, an insertion loss less than 2 dB and a return loss better than 12 dB in the narrow frequency band 8.9-9.2 GHz. Thus, this phase shifter demonstrates a good potential to be extended to the millimeter wave frequencies with less loss.