传输法模拟滤波器型输出回路的间隙阻抗频率特性

利用传输法把滤波器型输出回路等效为双端口微波网络问题,通过理论分析,数值模拟和冷测实验证明了S21平方后的曲线能定性反映滤波器型输出回路的间隙阻抗频率特性.从而在仿真设计阶段,可将S21设为优化目标,利用三维电磁仿真软件的参数优化功能实现精确设计滤波器结构,比相位法,场分析法更加快捷准确.传输法同样适用于矢量网络分析仪冷测滤波器的实验,可消除系统拆装及波导元件引起的误差,使测量更加方便准确.

Gap-Impedance Simulation of Output Circuit with Filter in Transmission Method

The output circuit with filter of the klystron cavity was modeled and approximated in the transmission method,based on the two-port microwave system.The dependence of the gap-impedance on working frequency was theoretically analyzed,experimentally evaluated,and numerically simulated on the basis of the newly-developed model.The results show that the square of the transmission-parameter,2,is capable of best describing the relationship between the gap-impedance and working frequency.We propose that the design of the output circuit with filter be simulated via optimizing the S21with a 3D electromagnetic software package,because when it comes the accuracy,simplicity,and efficiency of the structural design,the transmission scheme outperforms both the phase method and field-analysis technique.In addition,the transmission method can do a good job in the cold test of the filters with a vector network analyzer,because of its high accuracy,elimination of possible errors and user-friendliness.