大耦合孔同轴输出腔的3维解析分析

 在高功率微波器件中，通常采用大耦合孔的同轴微波输出腔，该腔为3维结构。采用场等效原理将腔体、耦合孔及其输出负载(行波边界)进行分区,每个区域中的场由界面上的磁流密度决定。采用格林函数积分法可得每个区域中的3维场,再由各个区域的场匹配方程求得腔体的谐振频率、特性阻抗、有载品质因数、模式分布等参数。为腔体的计算和设计提供一种计算模型。

3-D analysis on the coaxial output-cavity with large coupling hole

The coaxial output-cavity with large coupling holes is often used in the high power microwave devices. The structure of this cavity is three dimensional with travelling wave boundary, and it is very difficult to calculate its high frequency characteristics by lumped parameters and numerical methods. On this condition, a kind of analytical method is developed in this paper. According to equivalent principle of field the cavity is divided into five regular regions. The field in each region is produced by proper surface magnetic current density on the common interface and can be expressed as integral of Green functions. The magnetic fields of two adjacent regions are then matched on the common interface to obtain a set of integral equations. From the integral equations the resonant frequency of the cavity and the magnetic current density can be solved by mean of computer. And then other important parameters: Q value with load, characteristic impedance and the field distribution may be determined on the magnetic current density.