Electromagnetic scattering of a 3D spherical impedance cavity with a circular aperture by an arbitrarily located and oriented Hertzian dipole

The problem of the scattering of an arbitrarily oriented and located Hertzian dipole from an impedance cavity with a circular aperture satisfying different impedance values at inner and outer spherical surfaces is solved with a method of auxiliary sources (MAS). The study of that canonical problem with Leontovich boundary conditions answers the effects of the location of the excitation, aperture size, and boundary conditions on the resonance and radiation characteristics of the semi-opened spherical cavity. The proposed approach employs the distribution of the two perpendicular Hertzian dipoles on auxiliary surfaces representing the scattered field inside and outside the spherical cavity with a circular aperture. As the numerical results, the total radar cross section and the near field distributions are provided for different cases including the aperture size, source location, and boundary conditions. The resonance characteristics are analyzed. The method is validated by other approaches for the limit cases.