基于粒子模拟的X波段磁控管频谱畸变改进

Improvement of Frequency Spectrum Distortion in an X-Band Magnetron Based on PIC Simulation

针对一种X波段磁控管工作模式的频谱畸变问题,以谐振系统互作用空间结构参数和整管工作参数、冷热测数据为基础,基于CST微波工作室的粒子模拟仿真模块,建立了该管芯的基础数据三维模型;以阴极轴向高度、阴极发射面直径、阴极发射与工作磁场、工作阳极电压为变量,通过对各参数组合的整管粒子模拟过程信息和仿真结果的比较,分析工作状态时该管的谐振腔与输出波导内各模式振荡建立与稳定时的相对幅度与工作频率变化,发现阴极尺寸、阴极发射与工作磁场的不匹配,导致工作模式分裂或过强的竞争模式对工作模式的干扰,使工作模式频谱畸变。通过优化管芯主要结构参数与工作参数,适当增加阴极轴向高度和阴极直径,降低阴极表面轴向磁场,选取合理的阴极热发射范围,解决了该管工作模式的频谱畸变问题。

Aiming at the frequency spectrum distortion in an X-band magnetron,based on structure parameters of the resonance system,operating parameters of the magnetron,as well as the cold and hot test data,a basic data 3D model is built by using particle-in-cell(PIC)simulation module of the CST microwave studio.Taking the cathode height,cathode diameter,cathode emission,working magnetic field and anode voltage as variables,by comparing the PIC simulation process information and simulation results of the entire tube with various parameter combinations,the relative amplitude and operating frequency changes during the establishment and stability of the mode oscillation in the resonant cavity and output waveguide in working state are analyzed.It is found that the cathode size,cathode emission and working magnetic field do not match well,which leads to working mode splitting or strong disturbing from competitive modes,resulting in the frequency spectrum distortion of working mode.By optimizing the main structural parameters and working parameters,properly increasing the axial height and diameter of the cathode,reducing the axial magnetic field on the cathode surface,and choosing reasonable cathode thermionic emission range,the frequency spectrum distortion of working mode is improved.