Scattering of electromagnetic waves by spherical dielectric cavities with double-sided impedance boundary conditions

This study presents the scattering by arbitrarily oriented Hertzian dipoles from a spherical dielectric cavity with a circular aperture, bounded by different impedance conditions on its spherical surfaces. The formulation applies the method of auxiliary sources (MAS) together with Leontovich boundary conditions to investigate how source location, aperture geometry, dielectric constant, and impedance characteristics effect the resonance and radiation behavior of the semi-open cavity. The scattered fields inside and outside the structure are represented by orthogonal auxiliary dipoles distributed on auxiliary surfaces, formulated in accordance with Huygens's principle, which ensures accurate boundary enforcement while removing singularities in the integral equations. Numerical results are presented for a wide range of configurations, revealing the impact of aperture variation, dielectric media, boundary impedances and source placement on both the total radar cross section and near-field distributions. The resonance characteristics are systematically analyzed, and the approach is verified against established solutions in limiting cases. In comparison with conventional full-wave computational methods, the MAS provides high accuracy with significantly reduced computational time and memory usage. The results confirm the efficiency and reliability of the proposed algorithm for analyzing spherical dielectric cavities with impedance boundary conditions.