Comparative analysis of frequency-doubling gyro-TWTs operating at different cyclotron harmonics

In this paper we present the results of analysis of two frequency-doubling gyro-TWT schemes. Both of them are based on the doubling of the signal frequency. They are different in the cyclotron resonance harmonics used in each stage. In the first configuration, the input waveguide operates at the fundamental cyclotron resonance while the output waveguide operates at the second harmonic; a so-called 1-2 scheme. In the second configuration, the input waveguide operates at the second cyclotron harmonic while the wave excited in the output waveguide at the second harmonic of the signal frequency interacts with electrons at the fourth cyclotron harmonic (2-4 scheme).