Electromagnetic Scattering from an Anisotropic Uniaxial-coated Conducting Sphere

The scattering fields from an anisotropic uniaxial-coated conducting sphere by a plane wave are derived. The electromagnetic fields in uniaxial anisotropic medium and free space can be expressed in terms of spherical vector wave functions in uniaxial anisotropic media and isotropic medium. Applying the boundary condition in the interface between the uniaxial anisotropic medium and free space, the surface of the conducting sphere, the expansion coefficients of electromagnetic fields in uniaxial anisotropic medium are obtained, and then the expansion coefficients of scattering fields and radar cross sections can be obtained. Numerical results between this method and Mie theory are in good agreement as we expect. some numerical results are given in this paper. Introduction In recent years, there has been a growing interest in interaction between electromagnetic fields and anisotropic media, mainly due to its many applications in the fields of antennas and microwave devices, etc. As this is an interesting subject of many potential applications, there have naturally been some existing work, for instance, the analysis of two-dimensional geometries [1,2] and three-dimensional geometries [3-8]. In this paper, on the basis of electromagnetic fields in uniaxial anisotropic medium using spherical vector wave functions [6], electromagnetic fields in anisotropic uniaxial-coated conducting sphere are formulated and numerically studied in this paper. The present work in this paper serves as a further extension of the studies in [6], and the fields in free space can be deduced from the present results and then expressed in terms of spherical vector wave functions in isotropic medium [6,9]. Applying the boundary conditions of electromagnetic fields on the interface between uniaxial anisotropic medium and free space and on the interface of conducting sphere, all the field expansion coefficients in uniaxial anisotropic medium and free space are derived. Some numerical results are also obtained using the formulas and presented herein. One special case is considered, where the results obtained using the present method and the Mie theory [11] are compared to each other and a good agreement is observed.