Study of high-power Ka-band second-harmonic gyroklystron amplifier

Abstract

The self-consistent nonlinear theory of two-cavity high-harmonic gyroklystron amplifier has been developed. The efficiency and gain of a second-harmonic gyroklystron were calculated numerically. The results obtained were used to choose the optimal parameters of the experimental second-harmonic tube. The experimental study was carried out to test high-harmonic amplifier concept. Two-cavity 35 GHz second harmonic gyroklystron with the TE021 cavity mode has been designed and tested in pulse operation. Output power of about 260 kW with efficiency 18% and 17 dB gain have been produced at 72 kV beam voltage and 20 A beam current. Bandwidth of about 0.1% has been observed. The restriction of the output power, efficiency, and gain was caused by spurious oscillations excited in the second cavity in the TE011 mode at the fundamental cyclotron frequency