SCATTERING OF ELECTROMAGNETIC PLANE WAVE BY A CIRCULAR DISK WITH SURFACE IMPEDANCE

Abstract

In this investigation, scattering from a circular disk with surface impedance has been studied rigorously. The method of analysis is Kobayashi Potential (KP). The mathematical formulation yields the dual integral equations (DIEs). These DIEs are solved by using the discontinuous properties of Weber-Schafheitlin's integral. After applying the boundary conditions and projection, the resulting expressions, flnally, reduce to matrix equations for expansion coe-cients. The matrix elements are in the form of inflnite integrals with single variable. These are then used to compute the values of expansion coe-cients. The far fleld patterns of the scattered wave are computed for difierent incident angles and surface impedances for both E- and H-polarizations. To verify the results, we have computed the solution based on the physical optics approximation. The agreement between them is fairly good. The circular disk is a canonical scatterer in the fleld of electromagnetics and has been a subject of investigation since long time. It has a wide range of application in radars, and antennas, etc.. Electromagnetic fleld problems are generally deflned by Maxwell equations and boundary conditions. The surfaces with large conductivity can be approximated with surface impedance boundary condition. The impedance boundary condition relates the electric and magnetic fleld components tangential to the boundary through a surface impedance factor linearly. The use of surface impedance boundary condition (SIBC) in problems where electromagnetic wave penetration is low,