Improved spectral iteration technique for the scattering from metallic cylinders

The use of the EFIE (electric field integral equation) static solution, incorporating the correct edge behavior, as an initial estimate of the current distribution in an iterative scheme, is considered. The procedure for improving the initial form of the current density is developed by manipulating the integral equation in the Fourier transform domain. Imposing the static solution of the current as first step in the iterative solution for the Fredholm integral equation of the first kind means extracting the singular part of the equation and consequently improving the convergence. Diffraction by strips, semi-infinite conducting wedges, equilateral triangular and square cylinders is considered as illustrative examples and validations of the method which is efficient in the entire frequency range, including also the resonance region are discussed. The procedure, depicted with simplicity, is applicable to more complex structures like printed circuits on stratified dielectric supports, where the Green´s function is known in the spectral domain.