Direct calculation of permeability and permittivity for a left-handed metamaterial
TL;DR: In this article, an electromagnetic metamaterial was fabricated and demonstrated to exhibit a "left-handed" (LH) propagation band at microwave frequencies, a situation never observed in naturally occurring materials or composites.
Abstract: Recently, an electromagnetic metamaterial was fabricated and demonstrated to exhibit a “left-handed” (LH) propagation band at microwave frequencies. A LH metamaterial is one characterized by material constants—the permeability and permittivity—which are simultaneously negative, a situation never observed in naturally occurring materials or composites. While the presence of the propagation band was shown to be an inherent demonstration of left handedness, actual numerical values for the material constants were not obtained. In the present work, using appropriate averages to define the macroscopic fields, we extract quantitative values for the effective permeability and permittivity from finite-difference simulations using three different approaches.
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TL;DR: In this article, a lossy left-handed material slab is embedded between two semi-infinite dielectric media and the properties of the lossy material are given in detail and required equations for the electromagnetic plane wave propagation are derived to solve the problem.
Abstract: This article presents a theoretical and numerical discussion of the reflection and transmission analysis through a lossy left-handed material slab embedded between two semi-infinite dielectric media. The properties of the lossy left-handed material are given in detail and the required equations for the electromagnetic plane wave propagation are derived to solve the problem. The main important contribution of this article is the characterization of left-handed material that is different from its counterpart known in the literature. After introducing the left-handed material slab, the analytical solution is found for the powers carried by an electromagnetic wave. Then, the reflected, the transmitted, and the loss power are computed in terms of the incidence angle, the frequency, and the slab thickness in the numerical results with the emphasis on the loss factor.
12 citations
TL;DR: In this paper, the effective medium model based on homogenization of normal modes for spherical particles is used to determine the effective permittivity ϵeff and permeability μeff in the quasi-static regime.
Abstract: We investigate the effective parameters and quasi-static resonances for periodic arrays of dielectric spheres. The effective medium model based on the homogenization of normal modes for spherical particles is used to determine the effective permittivity ϵeff and permeability μeff in the quasi-static regime. Major features of ϵeff and μeff are characterized by the Lorentz-type anomalous dispersion around the frequencies pertaining to the leading-order electric and magnetic resonances, respectively. In particular, the anomalous dispersion is depicted by a resonance function associated with the spherical cavity. The underlying mechanism of quasi-static resonance is illustrated with the localized and dipole-like field patterns at the resonant frequencies. A comparison with the effective parameters for periodic arrays of dielectric circular cylinders is also discussed.
12 citations
TL;DR: In this article, a double negative multi-split based square split ring resonator is discussed, where the Rogers- RT 5880 is used as a dielectric medium, and the resonant frequencies are located from 2.5 to 2.7 GHz.
Abstract: Metamaterial is an innovation that makes today's world look forward to another research area extension. In this proposed article, a double negative multi-split based square split ring resonator is discussed, where the Rogers- RT 5880 is used as a dielectric medium. The metallic design is composed of copper material printed on the dielectric substrate. The resonant frequencies are located from 2.5 to 2.6, 4.4–5.0, 8.3–9.0, 10.3–12.3, 14.0–14.5 and 15.3–15.7 GHz. This unit cell shows negative values of effective permittivity, effective permeability, and refractive index. The design is observed with the electric field and magnetic field distribution with vector field representation and analyses with various rotation angles on the XZ plane, different substrate material, and the minimisation of the dimension.
11 citations
TL;DR: In this article, a reconfigurable terahertz (THz) metamaterial (RTM) was proposed to investigate its multifunctional electromagnetic characteristics by moving the meta-atoms of split-ring resonator (SRR) array.
Abstract: We propose a reconfigurable terahertz (THz) metamaterial (RTM) to investigate its multifunctional electromagnetic characteristics by moving the meta-atoms of split-ring resonator (SRR) array. It shows the preferable and capable adjustability in the THz frequency range. The electromagnetic characteristics of the proposed RTM device are compared and analyzed by moving the meta-atoms in different polarized transverse magnetic (TM) and transverse electric (TE) modes. The symmetrical meta-atoms of RTM device exhibit a resonant tuning range of several tens of GHz and the asymmetrical meta-atoms of RTM device exhibit the better tunability. Therefore, an RTM device with reconfigurable meta-atoms possesses the resonance shifting, polarization switching, electromagnetically induced transparency (EIT) switching and multiband to single-band switching characteristics. This proposed RTM device provides the potential possibilities for the use of THz-wave optoelectronics with tunable resonance, EIT analog and tunable multiresonance characteristics.
11 citations
TL;DR: In this paper, a coupled transmission line model capable of describing the effective medium properties, propagation and internal reflections, the internal noise distribution, and the noise factor is developed, and two analyses are provided, a numerical solution with limited physical insight and an approximation based on physical principles, and excellent agreement is obtained.
Abstract: Lossy metamaterial elements act as sources of Johnson noise, making such materials inherently noisy. A coupled transmission line model capable of describing the effective medium properties, propagation and internal reflections, the internal noise distribution, and the noise factor is developed. Two analyses are provided, a numerical solution with limited physical insight and an approximation based on physical principles, and excellent agreement is obtained. It is shown that the internal noise spectrum is modified as it couples to the electromagnetic wave, and that there can be no change in permeability without an increase in the noise factor. This result implies that metamaterials will require careful evaluation of their noise performance before use in practical devices.
10 citations
Cites background from "Direct calculation of permeability ..."
...μr = 1 - q(2) / {1 + κ ω0(2)/ω(2) - jω0/ωQ0} (10) Equation 10 is clearly identical to expressions commonly found in the literature, if q(2) is identified with the so-called ‘filling factor’ (see [1, 7], or the discussion of five separate models for μr in Sec....
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...The resonant elements are typically arranged in an array and a variety of effective medium theories [7-9] and homogenization methods [10-12] have been developed to recover the effective parameters with different unit cells....
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10,495 citations
TL;DR: In this paper, it was shown that microstructures built from nonmagnetic conducting sheets exhibit an effective magnetic permeability /spl mu/sub eff/, which can be tuned to values not accessible in naturally occurring materials.
Abstract: We show that microstructures built from nonmagnetic conducting sheets exhibit an effective magnetic permeability /spl mu//sub eff/, which can be tuned to values not accessible in naturally occurring materials, including large imaginary components of /spl mu//sub eff/. The microstructure is on a scale much less than the wavelength of radiation, is not resolved by incident microwaves, and uses a very low density of metal so that structures can be extremely lightweight. Most of the structures are resonant due to internal capacitance and inductance, and resonant enhancement combined with compression of electrical energy into a very small volume greatly enhances the energy density at critical locations in the structure, easily by factors of a million and possibly by much more. Weakly nonlinear materials placed at these critical locations will show greatly enhanced effects raising the possibility of manufacturing active structures whose properties can be switched at will between many states.
8,135 citations
TL;DR: A composite medium, based on a periodic array of interspaced conducting nonmagnetic split ring resonators and continuous wires, that exhibits a frequency region in the microwave regime with simultaneously negative values of effective permeability and permittivity varepsilon(eff)(omega).
Abstract: We demonstrate a composite medium, based on a periodic array of interspaced conducting nonmagnetic split ring resonators and continuous wires, that exhibits a frequency region in the microwave regime with
8,057 citations
TL;DR: In this article, an effective description for a metalodielectric photonic bandgap (PBG) material was developed for a semi-infinite and slab observables.
Abstract: An effective description is developed for a metalodielectric photonic bandgap (PBG) material far beyond the quasi-static limit of traditional effective-medium theories. An analytic approach, recently presented by the authors, is further advanced to provide the complete effective permittivity and permeability functions. Reflection and transmission coefficients are presented for both TM and TE oblique plane-wave incidence, based on the determination of the equivalent impedance for each lattice plane in the crystal and the transfer-matrix method for reconstructing the effect of successive lattice planes. An analysis of the semi-infinite and slab observables yields the anisotropic effective refractive index, effective permittivity, and effective permeability, thus completing the macroscopic description of the interaction of electromagnetic waves with the medium. Among the novel aspects of the analysis is the equivalence of our PBG system with a physically dispersive system at ultraviolet frequencies and the derivation and explanation of the development of high dispersive magnetization (permeability) for these media, independently of the microscopic magnetic properties of the metallic implants.
44 citations