A new wideband negative refractive index metamaterial for dual-band operation

Abstract

material where negative permittivity and negative permeability are tailored to have negative refractive index property in some certain frequencies. The negative refractive index property usually occurs where the permittivity and permeability are found to be negative. D. R. Smith and his colleagues constructed such composite material by utilizing repeated metallic wires and split-ring resonators to have negative permittivity and permeability. They claimed that negative permittivity can be achieved by repeated metallic wire inclusion and negative permeability can be obtained by numerous magnetic structures like π-shape, S-shape, Z-shape and other interesting shapes [3][4][5][6]. It is well known that metamaterials are formed by small unit cells that are arranged in a periodic form and the characteristics of each individual unit cell are very important for the overall material's performance. However, recently, in some specific applications like, antenna design or filter design, utilization of single metamaterial unit cell is one of the promising approaches instead of bulk metamaterial or array of unit cells [7][8][9]. Besides this, it is being applied in specific absorption rate (SAR) reduction in human head, cloaking an object electromagnetically, designing polarizer or absorber and many other interesting applications [10][11][12]. According to the applications, different types of alphabetic metamaterial unit cells with NRI property were proposed in the literature but not all of these designs show negative refractive index property in the C-and X-band ranges with wide bandwidth. For example, Chang-Chun et al. [3] demonstrated a π-shaped negative refractive index metamaterial but it works in the X-band only. Hayet Benosman et al. [4], presented an 'S' shaped NRI metamaterial that operates in the K u -band only. Abdullah Dhouibi et al. proposed a 'Z' shaped metamaterial for C-band only in [5] but it was not showing NRI property.Abstract A new wideband negative refractive index (NRI) metamaterial for dual-band operation is introduced in this study. Initially, a bare-H-shaped resonator was designed over the FR-4 substrate material. The refractive index curve for the unit cell, displays more than 3-GHz negative real peak from C-band to some portion of X-band. The proposed design also displays NRI property in the same frequency bands with wider bandwidth, when the Rogers RT 3010 substrate material was employed instead of FR-4 substrate material.

Double-E-Triple-H-Shaped NRI-Metamaterial for Dual-Band Microwave Sensing Applications

“…Here, E-shaped transverse slot metamaterial unit cells are used to enhance the performance of the array antenna. H-shaped resonator on FR-4 substrate material [31] was introduced by another group of researchers for dual-band application with negative refractive index (NRI) properties. Double U-H shaped design proposed in [32] with DNG Properties.…”

Realization of broadband polarization-insensitive negative refraction using water-based metamaterial

“…From then on, MMs have become of enormous interests since new physics and exotic EM phenomena are illustrated which are not existed in natural materials including negative refraction [4][5][6][7][8]. Negative refraction responses have typically been implemented using planar or tridimensional metal-dielectric isotropic MMs with periodic unit cells providing electric and/or magnetic resonances ranging from microwave to optical frequencies [9][10][11][12][13], and even ultraviolet [14]. All kinds of metal-dielectric MMs were successfully used to fabricate the MMs with negative refractive index [15][16][17][18].…”