An efficient aperture formulation for large scattering problems

A method for reducing the number of unknowns for large scattering problems while maintaining a predetermined computation time, using a smaller matrix formulation, is discussed. The suggested approach is based on an aperture. rather than surface formulation, with the electric aperture field as the primary unknown. One eliminates from the computation the components of the unknown for which the solution is known, leaving a minimal portion of the field to be computed, the aperture part of the field that is related to the fringe current component. It is found that the equivalent incident current serves as a major tool for simplifying the equations. The resulting integral equation uses the equivalent incident current over the truncated aperture as the driving function, and the fringe current portion of the electric field over this region is the only unknown.<>