Stability of scattering formulations with multiple elemental current excitations

The incident magnetic field can serve as an alternative to the incident electric field as the exciting function in electrical field integral equation formulations. For planar problems, the incident magnetic field is scaled to produce the equivalent incident current as the useful excitation function. The incident current can be split into subdomain basis functions, giving rise to a number of current distributions, called the pulse responses, which can be combined to synthesize the response to any incident field. This synthesis process is investigated with respect to its stability in the presence of finite errors generated in the course of computing the individual pulse responses. The accumulation mechanism of these errors is established by physical reasoning and a numerical study which supports the suggested physical mechanism. The error is accumulated in an oscillatory manner as basis functions are added farther away from the planar scatterer. The total error can be kept to fairly low levels.<>