INCREASING THE NRI BANDWIDTH OF DIELECTRIC SPHERE-BASED METAMATERIALS BY COATING

A new metamaterial topology is proposed, based on dielectric coated spheres. The effect of the coating is an increased negative permittivity and permeability bandwidth compared with the non-coated spheres. The influence of the dimensional parameters is analyzed, and the relation of each of them with the bandwidth is studied. The theoretical results are confirmed by full wave simulations using CST. A combination of the new topology with wires is used to reach an NRI bandwidth of about 23%. To the knowledge of the authors, to date this is the highest bandwidth reported in literature.