A 90-GHz Waveguide Variable Phase Shifter

A 90-GHz waveguide phase shifter based on a rotating half-wave retarder has been designed, manufactured, and tested. The rotating half-wave- and two external quarter-wave-retarders are made of iris polarizers. The design has been optimized using finite-element analysis (Ansoft HFSS), with measurements made using a millimetre-wave VNA. We achieve a phase shift that is flat to within 0.7/1.2deg over 80-95/75-100GHz