Analysis and simulation of an input coupler for a ka-band second harmonic gyroklystron amplifier

The input system, is a very important part for the gyroklystron amplifier. The driven signal is injected into the input cavity through the input coupler, which excites the RF field to modulate the electron beam. A input coupler for the Ka-Band second harmonic gyroklystron is proposed and studied by using three-dimensional electromagnetic code in this paper. High mode purity of a circular TE021 mode in an input cavity is obtained．