Circular Waveguide Polarizer for Gyrotron Traveling wave tube

A circular waveguide polarizer for high power millimeter wave is proposed in this paper. The elliptical-shaped structure converts the linearly polarized TE
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mode to a circularly polarized TE
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mode. This circular polarizer can be well connected to the helical corrugated waveguide in the Gyro-TWT. By optimizing the polarizer length and radius, a good simulation result is obtained with an axis ratio less than 1.2 in the frequency range of 27.4-31.5 GHz. In the operating band, the reflection coefficient is less than −40 dB and the phase difference is approximately 88–90 degrees. It has good transmission performance in the operating band.