Design of a ka-band second harmonic gyroklystron amplifier by using a self-consistent nonlinear simulation

The self-consistent nonlinear simulation of a Ka-band, second harmonic two-stage gyroklystron amplifier is presented in this paper. The beam-wave interaction in the gyroklystron is studied by using a self-consistent nonlinear simulation code GKLSC, and the electron bunching pictures of the different positions in phase space are demonstrated in detail. The effects of various parameters, such as drift tube length, input power, frequency, velocity ratio, guiding center radius, magnetic field strength, velocity spread and beam current on the electronic efficiency, gain, and output power are discussed. The simulated results show that the designed gyroklystron amplifier can obtain about 21% electronic efficiency, 43 dB gain, and 0.6% bandwidth, respectively. The performance of the designs is also confirmed by a particle-in-cell code.