| The study of the electromagnetic (EM) scattering characteristics of metamaterials in the vicinity of conducting geometries is of tremendous interest to the scientific community. The objective of this thesis is to present a theoretical analysis of the scattering characteristics of these metamaterials in the vicinity of conducting surfaces for different geometries and arrangements. This thesis will contribute towards advancements in the areas of cloaking, low observable antenna design, remote sensing and sensor devices in the microwave regime (operating between 1 - 10 GHz). The metamaterials considered in this study are of both dispersive and non-dispersive types. The dispersive type metamaterials are simulated by substituting the Drude/Lorentz model for the permittivity and the permeability of the material. The non-dispersive type has fixed values for the same parameters for the entire spectrum. In the first part of the analysis, the scattering characteristics of a metamaterial coated conducting cylinder with an intervening air gap will be presented. Subsequently, the scattering characteristics of a metamaterial coated conducting sphere with an intervening air gap will be presented. In reality, these air gaps may be implemented by styrofoam which has approximately the same dielectric characteristics as that of air (&egr;r=1.03). For both cylindrical and spherical cases, plane wave incidence has been considered. It can be shown that broadband reduction of backscattering and reduction of total scattering for a broad range of scattering angles are possible to achieve, thus giving astonishing results for cloaking and scattering reduction applications. In the final portion of this thesis, the scattering characteristics of a dispersive and lossy or non-dispersive metamaterial sphere or metamaterial coated conducting sphere in the vicinity of a conducting surface with the surrounding medium being air is presented. A technique based on method of images and multipole expansions is utilized to obtain the scattering characteristics for a circularly polarized (left or right) incident beam. The results show interesting possibilities for remote sensing and low observable antenna and radar applications for maritime purposes. |
