Direct and inverse scattering problems for spherical Electromagnetic waves in chiral media

TL;DR

This paper investigates the direct and inverse electromagnetic scattering problems involving spherical objects in chiral media, providing explicit solutions, approximations, and asymptotic analysis for both near-field and far-field data.

Contribution

It introduces explicit Green's functions, near-field approximations, and low-frequency asymptotic methods for inverse scattering in chiral media with spherical targets.

Findings

Derived exact Green's functions for chiral media

Obtained closed-form near-field approximations for small spheres

Developed low-frequency asymptotic formulas for inverse problems

Abstract

We study the direct and inverse scattering problems when the incident electromagnetic field is a time harmonic point- generated wave in a chiral medium and the scatterer is a perfectly conducting sphere. The exact Green s function and the electric far-field patterns of the scattering problem are constructed. For a small sphere, a closed-form approximation of the scattered wave field at the source of the incident spherical wave is obtained. These near-field results lead to the solution of an inverse problem. We also treat the same inverse problem using far-field results via the leading order term in the low-frequency asymptotic expansion of the scattering cross-section.