# Planewave scattering by an ellipsoid composed of an orthorhombic dielectric magnetic material

## TL;DR

This paper develops a method to analyze how an ellipsoid made of orthorhombic dielectric-magnetic material scatters plane waves, revealing how shape, size, and material anisotropy influence scattering, absorption, and extinction efficiencies.

## Contribution

It introduces an extended boundary condition method for scattering by anisotropic ellipsoids with scalar permittivity and permeability dyadics, providing detailed efficiency calculations.

## Key findings

- Multiple lobes appear in scattering patterns as size increases.
- Total scattering can be less than absorption for certain incident wave configurations.
- Shape and anisotropy significantly affect scattering and backscattering behaviors.

## Abstract

The extended boundary condition method can be used to study planewave scattering by an ellipsoid composed of an orthorhombic dielectric-magnetic material whose relative permittivity dyadic is a scalar multiple of its relative permeability dyadic. The scattered and internal field phasors can be expanded in terms of appropriate vector spherical wavefunctions with unknown expansion coefficients, whereas the incident field phasors can be similarly expanded but with known expansion coefficients. The scattered-field coefficients are related to the incident-field coefficients through a matrix. The scattering, absorption, and extinction efficiencies were calculated thereby in relation to the propagation direction and the polarization state of the incident plane wave, the constitutive-anisotropy parameters, and the nonsphericity parameters of the ellipsoid, when the eigenvectors of the real permittivity dyadic are aligned along the three semi-axes of the ellipsoid. As the electrical size of the ellipsoid increases, multiple lobes appear in the scattering pattern. The total scattering efficiency can be smaller than the absorption efficiency for some configurations of the incident plane wave but not necessarily for others. The nonsphericity of the object has a stronger influence on the total scattering efficiency than on the absorption efficiency. The forward-scattering efficiency increases monotonically with the electrical size for all configurations of the incident plane wave, and so does the backscattering efficiency for some configurations. For other configurations, the backscattering efficiency has an undulating behavior with increase in electrical size, and is highly affected by the shape and the constitutive anisotropy of the ellipsoid.