A mode-selective-circuit gyrotron-traveling-wave amplifier with high stability

This paper devotes to modeling and the stability study of a Ka-band TE01 mode gyrotron Traveling-Wave Tube (gyro-TWT) based on a modal selective circuit alternately loaded with lossy ceramic shells and metal rings. The linear theory and the self-consistent nonlinear theory are applied to analyze the stability of the equivalent interaction circuit. The study reveals that the lossy dielectric-loaded waveguide is with modal selective ability, and its propagation characteristics are similar to that of the circular empty waveguide. The internal feedback physics of the self-excited oscillations are revealed in the stability analysis. The consistency between the theoretical analysis and the experimental tests of American Naval Research Laboratory indicates the reliability of this study. The theoretical model in this paper brings guidance for future designing a gyro-TWT.