A Study on Electromagnetic Plane Wave Scattering by a Crack on Conducting Plane

This paper analyzes an electromagnetic plane wave scattering by a crack model on perfectly conducting plane and presents a simple formula for easily calculating two dimensional radar cross section from a material covered crack. Here, a narrow rectangular trough, which is filled by two-layered dielectric material, is utilized as the simple crack model to obtain the rigorous solution of the scattering field. In the formulation, we utilize the Kobayashi Potential (KP) method, which is an eigen function expansion method in terms of Weber-Schafheitlin type discontinuous integrals. Then the simple formula of the scattering field for the case that the aperture width is electrically very narrow is derived by approximating the rigorous solution. By utilizing the derived simple formula, the scattering characteristics for empty, partially material covered, and material filled crack models can be easily investigated.