Numerical analysis of electromagnetic scattering from three-dimensional perfectly conducting objects with concave-convex surface: The near field and the surface current density

The scattering properties of three-dimensional (3D) perfectly conducting objects, especially the near field and the surface current density, are analyzed by using the Yasuura method. First, the intensity pattern of the total electric field is compared with that of the total magnetic field in the extreme near region when a plane wave impinges on an object, and a significant difference between them, which cannot be observed in the far region, is clarified. Next, showing that the total magnetic field in the extreme near region has a strong pattern along the scatterer surface, it is pointed out that the scatterer shape is expressed as a strong pattern of the total magnetic field in the region. Moreover, partial deformation of the scatterer shape changes the characteristics of the surface current density markedly. This means that the surface current density is strongly dependent on the scatterer shape. Finally, by showing that the surface current density on an arbitrary observation surface is a composite characteristic of the surface current density on two specific surfaces which are orthogonal to each other, we clarify the inherent polarization dependence of the surface current density in 3D scattering problems. (C) 1999 Scripta Technica, Electron Comm Jpn Pt 2, 82(7): 23-30, 1999.