Using the method of modal parameters, developed earlier, equations for the Singularity Expansion Method (SEM) poles were obtained. Numerical investigation of solutions for the poles of the fist layer have shown good agreement with analytical and numerical results obtained earlier.

In this paper, we investigate the propagation of high-frequency current waves along a stochastic transmission line inside a rectangular cavity using as basis the model of a transmission line with the symmetry of the resonator. The stochastization of the line is created by a stochastically arranged chain of loads. Using similar models one also can take into account stochastic geometry of the line.

Apertures in shielding enclosures are an important issue for determining shielding efficiencies. Bethe’s theory describes the coupling via field excited dipole moments at the location of the aperture. This approach neglects the reaction of the dipoles on the exciting field and therefore violates energy conservation. This work emphasizes an analytical asymptotic approach for coupling between half-spaces through small apertures, which allows an understandable generalization of Bethe’s theory.