The expression of retroooupling coefficient of fiber-GRIN rod-reflector in coaxialcoupling is derived by ray-matrix method.
用光线矩阵方法推导了光纤-自聚焦棒-反射器在共轴耦合情况下的后向耦合系数；
2
The cutoff wavelength of the rectangular coaxial waveguide in the coupling region is calculated by boundary element method.
其耦合区为矩形同轴波导。 文中用边界元素法对矩形同轴波导的截止波长进行了计算。
3
This paper proposed a practical model for a high-directivity weak-couplingcoaxial microwave coupler, based on the principle of coaxial directional coupler and a precise theoretical analyzing process.