Comparison of real- and perfect-conductor approaches for scattering by a cylinder on a flat substrate

Abstract

Light scattering from circular cylinders (diameter sizes from 0.1λ to 4λ) on a conducting substrate are studied by means of a numerical solution of the electromagnetic problem based on the extended boundary conditions of the extinction theorem. Both the cylinder and the substrate are considered real conductors. The evolution of the scattering patterns and the source functions for several angles of incidence allows it to be compared with that found in previous research on perfect conductors. The study shows that, although some of the features are similar in both cases, important differences exist. We found that, for this geometry, the perfect-conductor assumption for real metals is correct only for light polarized perpendicularly to the plane of incidence (which in turn is assumed to be perpendicular to the cylinder axis). Parallel polarized light is far more sensitive to the optical properties of the surfaces, therefore producing different scattering features.