Analytical solution of electromagnetic scattering by a general gyrotropic sphere

Electromagnetic scattering by a general gyrotropic sphere is discussed in terms of spherical vector wave functions. From the source-free Maxwell´s equations and Fourier transform, the eigenvalue and eigenvectors of the electric field in a source-free gyrotropic medium can be obtained. The electromagnetic fields may then be obtained in terms of spherical vector wave functions in a source-free gyrotropic medium. Applying the continuous boundary conditions of electromagnetic fields on the surface between the free space and gyrotropic sphere, the spectral coefficients of the transmitted fields inside a gyrotropic sphere and the scattered fields in an isotropic medium (free space) can be obtained exactly by expanding spherical vector wave eigenfunctions. Numerical results are provided for some representative cases. Results from this study and those from an adaptive integral method are in agreement.