Electromagnetic Scattering by a Rotationally Symmetric Gyrotropic-Coated Impedance Sphere

Abstract

The work presents a full-wave investigation of an impedance sphere coated with a rotationally symmetric gyrotropic layer, exhibiting both electric and magnetic gyrotropies. A formulation based on the modal decomposition of fields in terms of spherical harmonics is presented. The scattered field is evaluated by matching the tangential field components at the gyrotropic layer to the impedance surface and the gyrotropic layer to free space interfaces. An extensive parametric investigation is thereafter carried out to evaluate the scattering characteristics with variation in the surface impedance and each of the tensorial gyrotropic parameters. The results show the dependence of the ripples, low RCS regions, and variation in scattering characteristics on the electrical and structural parameters of the configuration and provide valuable guidelines for the reduction and control of RCS.