双间隙耦合输入腔的计算与仿真研究

Equivalent Circuit Simulation of Double-Gap Coupled Input Cavity

根据微波电路及谐振腔电磁场基础理论,建立了双间隙耦合输入腔的等效电路模型,模型考虑了频率偏谐,外观品质因数失配以及电子注电导的影响。推导出间隙电压计算公式和输入端口匹配时腔体外观品质因数与腔体品质因数的关系。分别利用高频软件(HFSS)及粒子模拟软件(MAGIC3D)建立了仿真模型,进行了冷腔及电子注模拟,分析了电子注的电子负载效应对腔体参数的影响。理论计算与仿真与结果一致,证明了等效电路模型的准确性。

The double-gap coupled input cavity was modeled and simulated with an equivalent circuit,on the basis of microwave circuit and resonant cavity theory.The equivalent circuit model gave full considerations to the influencing factors,such as the frequency patialness,external Q-factor mismatch and beam-loading conductance.Accordingly,the gap voltage was formulated,and the relationship between the external Q-factor and the cavity Q-factor was derived when the input port is matched.Moreover,the input cavity was modeled and simulated with the software packages of high frequency structure simulator（HFSS）,and particle-in-cell（PIC） code（MAGIC3D）,respectively;and the cold cavity and electron beam were simulated to evaluate the impacts of the beam-loading on cavity parameters.The good agreement between the simulated and the calculated results shows the high accuracy of the equivalent circuit model.