Analysis of Input Impedance and Radiation Characteristics of a Dipole Embedded in and Near a Stratified Uniaxial Sphere

In this work, the Green’s function for a dipole in a stratified uniaxial anisotropic spherical configuration is evaluated, with the dipole in the anisotropic layer. The particular part of the Green’s function is computed by matching the electromagnetic fields at the source in the anisotropic layer. The homogeneous part of the Green’s functions is found by imposing boundary conditions at the anisotropic and isotropic layer interfaces. The source-free resonant frequencies of the transverse electric (TE) and transverse magnetic (TM) modes for the antenna configuration are also evaluated. The input impedance and fields radiated by the dipole in the multilayer anisotropic sphere are computed. The technique is also used for the evaluation of the Green’s function, input impedance, and radiated fields for a dipole located in the vicinity of the stratified uniaxial anisotropic sphere. The variation of input impedance, reflection coefficient, and excited modes with change in anisotropy is thoroughly investigated for both the antenna configurations. The excited modes in both the configurations are also characterized in terms of their quality factor, bandwidth, gain, and radiation efficiency. The radiation characteristics with change in anisotropy are also evaluated.