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.