Negative refractive index metamaterials using only metallic cut wires (original) (raw)
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Novel cut wires metamaterial exhibiting negative refractive index
We present, design and analyze a novel planar Left-Handed (LH) metamaterial in the microwave region. This metamaterial is composed of only cut metallic wires and is used under normal-to-plane incidence. Using Finite Element Method (FEM) based simulations and microwave experiments, we have investigated the material properties of the structure. Simultaneous negative values are observed for the permittivity e and permeability m by the inversion method from the transmission and reflection responses. A negative index n is verified in a bulk prism engineered by stacking several layers of the metamaterial. Our work demonstrates the feasibility of a LH metamaterial composed of only cut wires.
physica status solidi (b), 2007
A planar composite metamaterial consisting of bilayers of metal cutwire pairs and long wire pairs which are separated by a thin dielectric layer is designed and fabricated for microwave frequencies. The simulated and experimentally measured transmission spectra of the metamaterial and its individual components (cutwire-only and wire-only) indicates that the metamaterial exhibits a transmission band within the common stop bands of its components, and thus acts as a medium with negative index of refraction. The existence of n < 0 is further supported by a refraction experiment.
Symmetry breaking in metallic cut wire pairs metamaterials for negative refractive index
Metamaterials made of exclusively metallic cut wire pairs have been experimentally demonstrated to exhibit a negative refractive index at optical frequencies. However, other related works have not shown a negative index. In this paper, we propose an easy way to manipulate the magnetic and electric resonances of these metamaterials to produce a negative index. We show that judiciously breaking the symmetry of the structure allows tuning of both resonances leading to an overlapping between the negative permeability and negative permittivity regions. Numerical and experimental parametric studies of several cut wire pairs metamaterials are presented to validate our method at microwave frequencies.
Incidence dependence of negative index in asymmetric cut wire pairs metamaterials
Applied Physics Letters, 2009
Metamaterials made of asymmetric cut wire pairs have experimentally demonstrated a negative refractive index at microwave frequencies. In this letter, we begin by presenting the analogy between asymmetric cut wire pairs and S-shaped metamaterials by a simple unifying approach. Then, using simulations and experiments in the microwave domain, we investigate the dependence of resonances and retrieved effective index on the incident angle in asymmetric cut wire pairs. While it is found that resonances shift in frequency with increasing oblique incidence in the E-plane, it is shown that the structure is angle-independent in the H-plane.
A new planar left-handed metamaterial composed of metal-dielectric-metal structure
Optics Express, 2008
An improved planar structure of left-handed (LH) metamaterial is presented, and then designed and analyzed in microwave regime. In the anticipated LH frequency regime, the LH property is validated from the phenomena of backward wave propagation and negative refraction. To characterize the electromagnetic property of the planar metamaterial, we introduce the wedge method by constructing a wedge-shaped bulk LH metamaterial by stacking the planar LH metamaterials. The effective refractive index estimated by the wedge method is in excellent agreement with that retrieved by the inversion method from the transmission and reflection spectra.
Novel planar negative refractive index metamaterials
2005 IEEE Antennas and Propagation Society International Symposium, 2005
Planar periodic arrays of metallic elements printed on grounded dielectric substrates are presented to exhibit first-order left-handed modes with an equivalent negative refractive index (NRI) . The proposed structures dispense with the need for grounding vias and ease the implementation of completely planar (also called uniplanar) NRI metamaterials at higher frequencies. Full wave dispersion curves are presented. A verification of the left-handedness is presented by means of full wave simulation of finite uniplanar arrays using commercial software (HFSS). The cell dimensions are a small fraction of the wavelength (about λ/24) so that the structures can be considered as a homogeneous effective medium. The structures are simple, readily scalable to higher frequencies and compatible with low-cost fabrication techniques.
Investigation of negative index properties of planar metamaterials based on split-ring pairs
Applied Physics A, 2011
A low losses broadband planar negative refractive index metamaterial based on split-ring resonator (SRR) pairs is proposed and investigated experimentally and numerically at microwave frequency range. The transmission spectra of the single-layer SRR pairs were measured, and exhibited left-handed (LH) transmission passband clearly. The metal-dielectric-metal structure exhibits strong magnetic and electric responses simultaneously, and leads to negative permeability and negative permittivity. To further verify the LH properties of planer structure metamaterials, effect media parameters were retrieved, a refraction phenomenon based on a wedge-shaped model and negative phase advance between consecutive numbers of layers were also demonstrated.
Transmission measurements of a new metamaterial sample with negative refraction index
Physica B: Condensed Matter, 2010
We presented the microwave experiments with a new metamaterial composed of triangular split ring resonators (TSRRs) and wire strip at microwave regime. The transmission measurements were performed in free space for two LHM samples which have different number of TSRRs and wire strips. The experimental results show that the left-handed transmission peak stands in the frequency band where both the permittivity and permeability are negative. It is also observed that left-handed transmission band can be shifted if the number of TSRRs and wire strips are changed.