A low-order-singularity electric-field integral equation solvable with pulse basis functions and point matching

The conventional form of the electric-field integral equation (EFIE), unlike the magnetic-field integral equation, cannot be solved accurately with the method of moments using pulse basis functions and point matching. A new form of the EFIE is derived whose kernel has no greater singularity than that of the free-space Green's function. This low-order-singularity form of the EFIE, the LEFIE, is solved numerically for perfectly electrically conducting bodies of revolution (BORs) using pulse basis functions and point-matching. Derivatives of the current are approximated with finite differences using a quadratic Lagrangian interpolation polynomial. Such a simple solution of the LEFIE is contingent, however, upon the vanishing of a linear integral that appears when the original EFIE is transformed to obtain the LEFIE. This generally restricts the applicability of the LEFIE to smooth closed scatterers. Bistatic scattering calculations performed for a prolate spheroid demonstrate that results comparable in accuracy to those of the conventionally solved EFIE can be obtained with the LEFIE using pulse basis functions and point matching provided a higher density of points is used close to the ends of the BOR.