边值积分方程的奇点与波导截止波数

The Singular Point of Boundary Integral Equations and the Cutoff Wave Numbers of Waveguide

证明了导体柱面外部散射场Ｅ＿ｚ￣（ｓ）、Ｈ＿ｚ￣（ｓ）的边值积分方程的奇点ηＥ和ηＨ相等．从而提出用解边值积分方程的方法求波导截止波数．其中对Ｅ模和Ｈ模可共用一套程序，只需调节主对角线元素的符号．Ｅ模的截止波数同时就是外部散射问题的奇点．

A result is proved that the singular pointsηE and ηH of the boundary integral equations of the outer scattering fields E_z￣(s)and H_z￣(s) of a cylindrical conducting surface are equal. Then a method for solving the cutoff wave numbers of waveguide is suggested, in which the same one program may be used commonly for E mode and H mode. The only change needed is the adjustment of the sign of the main diagonal elements. The cutoff wave numbers of E mode are also the singular points for the outer scattering problem.