Numerical evaluation of aperture coupling in resonant waveguides and frequency perturbation analysis

This paper presents a new formulation for numerical evaluation of the coupling between two identical resonant waveguides by a small elliptical aperture in a plane common wall of finite thickness. The aperture coupling is expressed in terms of electric and magnetic dipole moments and polarizabilities using Carlson symmetric elliptical integrals. Slater's perturbation method is applied to find the frequency changes due to apertures of finite thickness on the waveguide wall.