Design and experimental demonstration of a TEM-TE phase shifter for high-power microwave applications.

A novel phase shifter used to adjust the output phase of high power microwave (HPM) is investigated. The phase shifter is composed of two different circular polarizers, one of which can convert the coaxial transverse electromagnetic mode (TEM) into circularly polarized (CP) TE mode, and the other one can realize the transformation between the CP TE mode and the rectangular TE mode. The two circular polarizers are connected by a circular waveguide, and the TEM-TE circular polarizer can rotate around its axis continuously. In this way, the phase shifter can adjust the output phase of the TE mode in the range of 0°-360°. In this paper, the principle of a phase shifter working at 1.57 GHz, as well as the experimental results, is demonstrated. The experimental and simulation results are in good agreement. At the central frequency, the transmission efficiency in this range of phase-shifting process is over 94.6%, and the power-handling capacity is as high as 1.5 GW. This novel phase shifter is of interest to HPM spatial power combination technologies.