Realization of spherical D′B′ boundary by a layer of wave-guiding medium

Abstract

In this paper the concept of wave-guiding medium, recently introduced for planar structures, is defined for the spherically symmetric case. It is shown that a quarter-wavelength layer of such a medium serves as a transformer of boundary conditions between the two interfaces. As an application, the D′B′-boundary condition, requiring vanishing of normal derivatives of the normal components of D and B field vectors, is realized by transforming the DB-boundary conditions. To test the theory, scattering from a spherical DB object covered by a layer of wave-guiding material is compared to the corresponding scattering from an ideal D′B′ sphere, for varying medium parameters of the layer.