Numerical and experimental investigation of the scattering of electromagnetic waves by perfectly conducting ensembles

Abstract

ABSTRACT In this thesis, the problem of electromagnetic scattering from and ensemble of perfectly conducting smooth bodies is investigated numerically and experimentally. Numerical part of the work done is based on a theory which employes multipole expansion techniques. The scattering problem is considered as a problem of radiation from the induced surface sources. The re-radiated fields are expanded in terms of spherical vector wave functions. The unknown multipole coefficients are determined from the linear relations 'obtained from the properties of the spherical vector wave functions, expansion of the incident field and surface current relations. Numerical techniques are developed for use of a general ensemble of arbitary bodies. Due to difficulties arising from the limitations of the available computer, toroidally symmetric ensembles are investigated using a similar technique to the one used for the general problem. Back-scattering cross-sections are measured by a method based on comparison of thescattering from scandard scatterers. (i.e. spheres) and the ensembles. A satisfactory agreement is obtained with numerical results.