Novel low loss broadband polarization independent fishnet negative index metamaterials at 40 GHz (Abstract)

Metamaterials are artificially engineered materials, which exhibit properties that do not exist in nature. These composite structures give access to control the internal electromagnetic properties, i.e. the electric permittivity ε and the magnetic permeability μ, in such a manner that a variety of attractive phenomena like negative refraction and cloaking can take place. In recent years, negative index metamaterials (NIM), which have negative refractive index n rising from ε<0 and μ<0 simultaneously, have aroused interest of many researchers due to the promising planar perfect lens application that may overwhelm the diffraction limited conventional lens [1]. The basic idea to achieve negative μ is to excite circular currents that generate a magnetic resonance, whereas negative ε can be produced using continuous metallic wires for frequencies below the plasma frequency. This concept was first concretized by Smith et al. who utilized a combination of split ring resonators and metallic wires [2] and later by Dolling et al. using cut-wire pairs [3]. Another NIM structure called fishnet was reported in the same year by Zhang et al. and showed better performance due to the combined electromagnetic response of the wires and slabs [4]. In this study, we present a novel polarization independent fishnet NIM with both negative ε and μ at 40 GHz. The structure is investigated numerically and experimentally and shows large bandwidt