Ka 波段过模慢波结构色散曲线的数值求解

摘要

Backward wave oscillator with over-mode Ka-band high power microwave (HPM)generally outputs mixed TM0n modes,it has high energy conversion efficiency,but it can′t ensure the purity of output modes.However,it is necessary for high radiation efficiency that the microwave input to the radiation terminal is certain single and pure.So it is hard to put these HPMsources into application.In order to solve this problem,a design method for compact hybrid modes converter of purifying TM0n mixed modes was proposed.With this method,the TM01,TM02 and TM03 mixed modes can be converted into pure circular waveguide TM01 mode efficiently on the condition of high power capacity and wide wave band.This method also reduces the modes purification difficulty in the design of the HPMsources.%运用场匹配法，结合 Ka 波段过模慢波结构的实际情况，进行轴对称周期慢波结构色散关系的理论推导，得到了一种快速、准确计算适应 Ka 波段过模慢波结构的色散特性计算方法。根据推导结果，采用MATLAB 程序编程计算了 Ka 波段过模盘荷波导的色散曲线。将计算得到的色散曲线与成熟的商业软件计算得到的结果进行了对比，两者误差在2％以内，验证了数值算法的可靠性。计算得到的色散曲线可以辅助选取 Ka 波段微波源的结构参数，对器件设计有一定参考价值。