Theory of gyro-travelling-wave tubes at cyclotron harmonics

Abstract The generalized theory of gyro-travelling-wave tubes operating at arbitrary cyclotron harmonics is developed taking into account the transverse drift of electron guiding centres. In the framework of small-signal theory, the dispersion equation is obtained and analysed and a problem of spurious counterpropagating waves excitation is discussed. The results of the large-signal theory are presented, which predict a high efficiency of operation at the first four cyclotron harmonics.