Study of the output characteristics of a Ka-band, second harmonic three-cavity gyroklystron amplifier

The optimal design of the output cavity of a Ka-band second harmonic three-cavity gyroklystron amplifier is finished based on beam-wave interaction characteristics of the amplifier in this paper. The diffraction Q variation with the size of the diffraction output aperture at the end of the output cavity is calculated. By PIC simulations, the output characteristics of the amplifier such as the frequency response etc. are analyzed. At 35.0GHz, a peak output power of more than 220kW with an electronic efficiency of about 23%, and a gain of 23dB, and a 3-dB bandwidth of 110 MHz (0.3%) is obtained with a 70-kV, 15-A electron beam at a magnetic field of 0.685T and a beam velocity ratio of a 1.45.