PMOBG法用于类矩形波导的模式分析

用边界形状摄动法（PMOBG）研究具有一维扰动壁的矩形波导问题并对其进行了模式分析.为此，首先将边界条件变换为可以用摄动方法处理的形式，再用伸缩参量法将支配方程分解为ε０阶和ε１阶问题，借助于微分方程的可解性条件得到解.作为与规则矩形波导的比较，讨论了边界形状扰动对波导中的模式简并、传输参量和场结构的影响，并将这一影响归结为对边界形状摄动因子（PFBG） 和相对截止波长摄动因子（PFRCW）的分析.

Mode Analyses of Quasi-Rectangular Waveguides by Using PMOBG

Perturbation method of boundary geometry (PMOBG) is used in rectangular waveguides with one-dimension perturbed walls and mode analyses are made.The boundary conditions are transformed into perturbation form firstly.Then the governing equation is separated into ε0 and ε1 order problem by using the method of strained parameters.Finally the solution is obtained via the solvability conditions of differential equation.Moreover,the effect of boundary perturbation on mode degeneration,transmitting parameters and field structure is discussed by comparing with regular rectangular waveguides.The results show that the effect is able to come down to analyzing two perturbation factors,i.e.perturbation factor of boundary geometry (PFBG) and perturbation factor of relative cut-off wavelength (PFRCW).