该文从分析损耗介质加载金属圆波导中电磁波传输特性出发,应用回旋行波管放大器小信号色散方程,研究损耗介质加载结构TE01模回旋行波管放大器绝对不稳定性振荡和回旋返波振荡对器件稳定性的影响。结果表明:损耗介质的加载,可以提高绝对不稳定性起振电流,提高的幅度依赖于工作磁场偏离饱和磁场的程度、电子束横纵速度比等;增加波导损耗介质加载的厚度,可以提高竞争模式的回旋返波起振长度。合理选择波导的损耗层厚度、介电常数以及回旋行波管的工作电压、工作磁场和电子束横纵速度比,可以有效兼顾带宽和抑制不稳定性,保证回旋行波管放大器稳定工作。
This paper, with the analysis of the propagation characteristics in a lossy cylindrical waveguide and using small-signal theoretical dispersion relation, presents study on the device stability with influence of the absolute instability and the backward wave oscillation in TE01-mode lossy dielectric-load gyrotron traveling wave amplifier. The numerical results show that lossy dielectric-load can heighten the start oscillation current of absolute instability, and increase depends on the magnetic field strength and the perpendicular-to-parallel velocity ratio of the electrons; The thickness of the lossy waveguide increases the start oscillation length of backward wave oscillation. The combined appropriate selection of the lossy waveguide thickness, permittivity, voltage, the applied magnetic field and the velocity ratio can effectively give attention to bandwith and instability to ensure the stable operation of the gyrotron traveling wave amplifier.