Compact circular polarizer based on cross-shaped slot for high-power microwave applications

A compact high-power waveguide circular polarizer working at the C-band is presented in this paper. By introducing a split-ring slot and an orthogonally crossed rectangular slot into a circular waveguide, high transmission efficiency and 90° phase difference of two linearly polarized orthogonal TE₁₁ modes are achieved by using the polarizer within a half wavelength. In the meantime, the power handling capacity of the designed polarizer is expected to be over 120 MW, which can be applied in the high-power microwave region. The designed circular polarizer is fabricated and measured by the cold test; the results of experiments and simulations agree well with each other. It is shown in the experiments that the axial ratio is less than 0.9 dB, the voltage standing-wave ratio is less than 1.2, and the conversion efficiency is over -0.15 dB at 4.2-4.4 GHz.