Scattering analysis of circular apertures excited by off-axis sources by means of dual integral equations and analytical regularization.

The transmission of the electromagnetic field through a circular aperture in a perfectly conducting plate is evaluated through a rapidly convergent formulation in exact form. The source (a circular loop of constant current) and the receiver of the electromagnetic field can be arbitrarily placed in the two half spaces. By applying the equivalence principle, the problem is first formulated in the Hankel transform domain, obtaining a set of dual integral equations having as unknown the equivalent surface magnetic current density defined on the aperture. The set of dual integral equations is regularized in a second-kind Fredholm integral equation through the application of the method of analytical regularization. The efficiency of the formulation is further improved by adopting suitable techniques to accelerate the computation of all the integrals involved in the solution of the problem.This article is part of the theme issue 'Analytically grounded full-wave methods for advances in computational electromagnetics'.