过模结构表面波振荡器模式选择

过模结构能提高器件的功率容量和工作频率, 能使器件工作在低磁场状态, 越来越多的器件采用过模结构.但是过模结构允许多个模式同时存在, 这可能会引起模式竞争问题.本文通过理论分析和数值计算, 研究了过模结构模式选择问题.计算结果表明, 通过选择合适的结构参数和电参数, 使得器件工作在行波状态, 可以实现不同横向模式的选择.在此基础上, 通过选择合适的电子束和结构参数, 能实现不同纵向模式的选择.对计算结果进行了粒子模拟验证, 与理论分析符合较好, 达到了模式选择的目的. 关键词： 过模结构 模式选择 色散关系 表面波振荡器

Mode selection in surface wave oscillator with overmoded structure

More and more overmoded structures have been adopted in electronic vacuum devices because they can increase the power capacity and the frequency of the output signals. Overmoded structure device can more easily work in a low magnetic field. Overmoded structure may cause mode competition, which will reduce the output power. Mode selection in overmoded structure is studied in this article. Dispersion relation is obtained and solved numerically. The results show that the appropriate selection of working point that ensures the device working in a traveling wave state can realize transverse mode selection and appropriation selection of parameter of electron beam and the structure can realize the axial mode selection. The calculation results are verified by particle simulation.
Keywords： overmoded structure mode selection dispersion surface wave oscillator