A novel T-shaped high-power waveguide phase shifter with continuous linear phase adjustment.

A novel T-shaped high-power waveguide phase shifter is investigated in this paper. The phase shifter consists of straight waveguides, four 90° H-bend waveguides, a stretching metal plate, and a metal spacer linked with the stretching metal plate. The entire structure for the phase shifter is symmetrical along both sides of the metal spacer. The phase-shifting principle for the phase shifter is to change the microwave transmission path by moving the stretching metal plate and then realize the linear phase adjustment. An optimal design approach of the phase shifter based on the boundary element method is described in detail. On this basis, a T-shaped waveguide phase shifter prototype with a center frequency of 9.3 GHz is designed. Simulation results show that the phase shifters can achieve 0°-360° linear phase adjustment by altering the distance of the stretched metal plate to 24 mm, and the efficiency of power transmission is more than 99.6%. In the meanwhile, experiments were conducted and the test results are in good agreement with simulation results. The return loss is more than 29 dB, and the insertion loss is less than 0.3 dB at 9.3 GHz in the entire phase-shifting range.