360° Phase Shifter Design Using Dual-Branch Switching Network

This letter presents a reflective-type phase shifter with single-stage varactor diodes at the reflective networks. Dual-branch switching network is proposed and cascaded to the output of the phase shifter. The switching network is composed of a quarter-wavelength transmission line branch and a phase inverter branch. Phase inverter produces additional 180 degrees phase delay to the phase shifter. A single branch in the switching network is selected and directed to the output port one at a time. Simulations and experimental results demonstrate that insertion loss of the proposed phase shifter is constant, irrespective of branch chosen. The measured insertion loss variation is less than +/- 0.5 dB over phase shift tuning range of 360 degrees at 2.45 GHz.