Analytical and numerical investigation of the radiation and scattering from concentric metamaterial cylinders excited by an electric line source

An antenna configuration consisting of an arbitrarily located electric line source radiating in the presence of a pair of concentric metamaterial cylinders is investigated analytically and numerically. The near- and far-field properties of these structures are analyzed through an investigation of such parameters as the total radiated power, directivity, and total as well as differential scattering cross sections. The results obtained for these metamaterial structures are compared to those for the corresponding structures made of conventional materials. It is shown that electrically small concentric metamaterial structures can be designed to be resonant and to possess advantageous radiation and scattering characteristics in contrast to the corresponding structures made of conventional materials. More specifically, it is shown that metamaterial structures lead to significant enhancements of the total radiated power as well as the total and differential scattering cross sections. Moreover, the feasibility of controlling the directivity pattern of the electrically small metamaterial structures through appropriate locations of the electric line source is demonstrated. The effects of the dispersion and loss present in the metamaterials are taken into account to study the bandwidth properties of these resonant configurations.