Physical preconditioning for modeling 2D large periodic arrays

We investigate diffraction effects on truncated periodic structures at the field operator level. A physically based approximate operator inverse of the electric field integral equation (EFIE) is used either to obtain an accurate first estimate of element currents, or as a preconditioner for a more rigorous, iterative solution. To illustrate, we analyze linear arrays of cylindrical elements constituting antennas or periodic structures with arbitrary element geometry and excitation, though the method can be extended to 3D problems. We show the reduction in the matrix solution time that is achieved, and also discuss the physical insight into array truncation effects that the method provides. The MoM matrix and preconditioner, once constructed for a given array, are excitation independent and may be used repeatedly to obtain or analyze element current distributions, element tapering and scanning effects, element input impedances, active input impedances, element-failure impact on the radiating system, or coupling between element pairs in a finite array.