Design of a High - Power , High - Gain , Frequency - Doubling Four - Cavity Gyroklystron

In this paper we consider the design of a four-cavity microwave circuit for a high-gain K-band gyroklystron. The goal is to use this device to test a high gradient linear accelerator structure. The frequency doubling circular gyroklystron uses a beam voltage of 500 kV, beam current of 200 A in the circular TE011 mode and provides an output in the TE021 mode. We study the behavior of the four-cavity circuit for different values of perpendicular to parallel velocity ratio (α= V⊥ / Vz ). These tubes are required to produce 20 MW of power in 1μs pulses at a rate greater than 120 Hz and at a frequency of 22.848 GHz. Maximum efficiency of 38% and large signal gain of 60 dB were achieved for a velocity ratio equal to 1.4.