Fast computation of modified Green's function for generalized source integral equation solvers

A technique for the fast computation of modified Green's function arising from the generalized source integral equation (GSIE) formulation is proposed. The method is based on an efficient sampling and tabulation of the modified Green's function, which comprises two components: a direct free-space component and an additional contribution by electric and magnetic sources designed to “shield” the source from certain observation regions. The efficient sampling of the sum of both contributions is performed by using non uniform grids designed in accordance with the wave-field phenomenology unique to the source-“shield” configuration. The proposed method's performance is demonstrated for representative examples.