Scattering by imperfectly conducting and impedance spheroids: A numerical approach

An approximate numerical method for treating the problem of scattering from spheroids with impedance boundary conditions is presented. Initially, the electric surface currents are determined from the solution of the H field integral equation and neglecting the effect of the magnetic surface currents. The impedance boundary conditions are then used to obtain the magnetic surface currents from the computed electric currents. The method is applied to both spherical and spheroidal objects of varying surface impedances and the computed results are compared with the analytic or the direct integral equation solutions. It is found that the accuracy of the results is reasonable, but depends on both the object's geometry and its surface impedance. The results also show that the method predicts the backscattered field accurately, for all surface impedance types. Representative computed data for the bistatic and the backscattered fields of spheroids with different axial ratios and surface impedances are also presented.