Beam-wave interaction analysis of gyrotron-traveling-wave tube based on a lossy dielectric-lined waveguide
基于损耗介质加载波导的回旋行波管放大器的互作用分析

A lossy ceramic-loaded waveguide is positive to promote the stability and performance of the gyrotron traveling-wave amplifier (gyro-TWT). In this paper we develop the electron cyclotron maser linear theory on the basis of the field expressions in the lossy ceramic-loaded waveguide. By systematic numerical calculation, we find that both the field patterns and the dispersion curves have one-to-one mapping relation between the modes in ceramic-loaded waveguide and that in empty cylindrical waveguide. With the Laplace transform, the linear theory could calculate the field profile and the threshold of an absolute instability oscillation. The linear theory is also used to study the influence of the magnetic, current and ceramic layer on the amplification characteristics. These results are promotive to the application of the lossy ceramic in a gyro-TWT and the development of the high stable gyro-TWT.