Spectral-domain asymptotics for electromagnetic scattering from a point-source excitation target coated with a uniaxial electric anisotropic medium based on physical optics

By combining the spectral-domain method and asymptotic technique, we developed a physical optics (PO) algorithm to determine the scattered electromagnetic field from the uniaxial electric anisotropic medium (UEAM) coating under point-source excitation. To realize the proposed algorithm, first, the spectral-domain solution of an infinite PEC plane coated with a UEAM layer under point-source incidence, such as a magnetic dipole, is computed. Simultaneously, the reflected, transmitted, and secondary scattered fields generated in this planar multilayer structure are analyzed in detail, describing the physical image of propagation process concerning varied modes of electromagnetic wave inside and outside the dielectric layer innovatively. Second, using the saddle point evaluation, the asymptotic calculation of the scattering for the infinite medium-coated plate is realized in the spatial domain. Third, based on the tangent plane approximation employed in the PO method, any discretized surface patch of the scatterer can be estimated as an infinite UEAM-coated PEC plate. Subsequently, we depict the outer surface of any scattered target as the constitution of countless tiny triangular facets to match this proposed method. Finally, the total scattered fields are obtained by the field superposition of the overall illuminated facets under point-source excitation. Compared with reference solution, the proposed method is validated, and the simulation results of the representative shapes coated with the UEAM layer from a point source are presented .