A thin wire array and magnetic host structure with n<

Abstract

Construction of artificial media possessing a negative index of refraction can be simplified by using a nonconducting ferrimagnetic host medium to provide a negative permeability and an array of conducting wires to provide a negative permittivity. The interaction between the ferrimagnet and the wire array, which destroys the negative permittivity of the wire array, can be overcome by cladding the wires with an insulating, nonmagnetic jacket. Calculations of the propagation constants and transmission coefficients for a square array of cladded wires in a ferrimagnetic host are presented. The calculations are near exact for wavelengths significantly greater than the lattice parameter of the wire array. For wires a few microns in diameter, a lattice constant of 0.8mm, and an appropriate ferrimagnetic host in a biasing magnetic field, a transmission band 0.5GHz wide centered near 16GHz exhibits a negative index of refraction. Losses in the ferrimagnet and impedance mismatch to vacuum limit the peak transmission amplitude ratio through a slab 3.0cm thick to ≈3%.

Active and Tunable Metamaterials

“…Dewar first proposed the ferrite-based metamaterial as shown in Figure 4(a) and gave the theoretical expressions of the effective parameters and analyzed the interactions of the ferrites and wires [31,32]. Rachford et al and Cai et al numerically investigated the electro magnetic wave propagation properties of such metamaterials [33,34] with minor modification (see Figure 4b) for the easy fabrication.…”

“…On the other hand, some researchers proposed ferrite-based metamaterials, that is, substituting ferrites such as yttrium iron garnets (YIG) for the SRR structures to obtain the negative permea bility [31][32][33][34][35][36][37][38]. Dewar first proposed the ferrite-based metamaterial as shown in Figure 4(a) and gave the theoretical expressions of the effective parameters and analyzed the interactions of the ferrites and wires [31,32].…”

“…[28], (c) structural shifted structure [29], and (d) THz structural shifted structure [30]. [31,32], (b) modification achievements [34], and (c and d) experimental demonstrations [35,36]. [39], (b) double negative structure [40], and (c and d) dual-band structures [41,42].…”

Multi-Band Negative Refractive Index in Ferrite-Based Metamaterials

“…Hence, the possibility of producing NRI metamaterials with gyromagnetic materials has been widely discussed in theory and many structures have been proposed [28][29][30]. As the most typical gyromagnetic materials, ferrites were used to substitute for SRRs to provide a more dynamically tunable negative permeability [31,32].…”

Control over magnetic spectrum of multilayer magnetic film metamaterial

“…Different geometries of such structures have also been suggested. 11,12 Currently, metamaterials comprising ferromagnetic inclusions are widely employed as radar absorbers 13 and controllable electromagnetic materials, 14 with a full-wave simulation techniques typically employed instead of the equivalent circuit approach. As a whole, the problem of understanding of electromagnetic properties of such metamaterials has not been well studied, and further experimental and theoretical studies are needed.…”