微波器件微放电阈值功率自适应扫描方法

传统的粒子模拟软件在获得微放电阈值时需要进行多次微放电模拟，而且不具备自动功率扫描功能，在不考虑电子运动所产生的自洽场的情况下，提出了一种微波器件微放电阈值功率自适应扫描方法，对同一微波器件中的电磁场只计算一次并重复利用，改变输入功率，获得不同功率下的粒子数目变化的趋势，结合阈值功率判断方法，进而能够快速获得微放电阈值。首先，采用MSAT粒子模拟软件计算单位功率下微波部件中的电磁场分布，接着利用蛙跳法求解粒子运动轨迹，然后结合二次电子发射模型确定出射粒子数目。在微放电模拟过程中对粒子数目曲线进行分析，建立微放电阈值判据方法，根据二分法改变输入功率使得粒子模拟软件在给定初始功率后自动给出微放电阈值。以微波阶梯阻抗变换器与同轴腔体滤波器为研究对象，采用该方法分别计算其微放电阈值并与实验结果进行对比，结果表明，该方法具有准确性。

Adaptive scanning method for multipactor threshold prediction in microwave devices

Without the power scanning function, the traditional Particle-in-Cell simulation software needs to perform many times in order to achieve multipactor threshold prediction. Therefore, an adaptive scanning method is proposed without considering the self-consistent field generated by electrons. Under the effect of the electromagnetic field distribution calculated by MSAT, the electron motion is tracked and updated with leapfrog algorithm. Secondary electrons are released once electrons reach the boundaries of the simulation region. The criterion for determining multipactor occurrence is established according to the particle number curve via the multipactor simulation. Meanwhile, the power input is adaptively adjusted by the bisection method so that the multipactor threshold can be automatically determined with a given initial power. For verification, multipactor thresholds of stepped impedance transformer and coaxial cavity filters obtained with adaptive-scanning method are compared with experiments. And the simulation results accord well with the experimental data.