Tunable NRI Wedge Made of Metallic Wires in a Ferrite Host: Lens Structure, Experimental Demonstration, and Scanning Antenna / Spectral Analyzer Applications

摘要

Since the first experimental demonstration by Shelby et al. [1], negative refractive index (NRI) metamaterials have spurred huge interest and led to many novel theoretical and practical concepts and applications [2, 3]. The vast majority of these NRI metamaterials have been constituted of small resonators, either loosely coupled (split-ring and wire particle type structures) or tightly coupled (capacitor and inductor transmission line type structures). Since these structures suffer from a number of limitations, in terms of performance and manufacturing, alternative metamaterial structures, exhibiting superior or complementary properties, are highly desirable. Recently, Dewar theoretically proposed a novel NRI metamaterial where the negative permittivity was provided by an array of metal wires [4] while the negative permeability was provided by the inherent negative permeability of a ferrite medium between the resonance and anti-resonance frequencies [5]. This paper presents a full-wave demonstration of this NRI metamaterial, along with a preliminary corresponding lens experimental setup, and suggests possible subsequent applications of this lens.