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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Dissertation•
10 Mar 2009
TL;DR: In this article, the authors presented a theoretical and numerical analysis of parameters of a rectangular microstrip antenna with bianisotropic substrate, and including simultaneously the superconducting patch.
Abstract: This work presents a theoretical and numerical analysis of parameters of a rectangular microstrip antenna with bianisotropic substrate, and including simultaneously the superconducting patch. The full-wave Transverse Transmission Line TTL method, is used to characterize these antennas. The bianisotropic substrate is characterized by the permittivity and permeability tensors, and the TTL gives the general equations of the electromagnetic fields of the antennas. The BCS theory and the two fluids model are applied to superconductors in these antennas with bianisotropic for first time. The inclusion of superconducting patch is made using the complex resistive boundary condition. The resonance complex frequency is then obtained. Are simulated some parameters of antennas in order to reduce the physical size, and increase the its bandwidth. The numerical results are presented through of graphs. The theoretical and computational analysis these works are precise and concise. Conclusions and suggestions for future works are presented.
2 citations
Cites background from "Direct calculation of permeability ..."
...Este material não foi uma substância natural, como esperado por Veselago, foi uma estrutura efetivamente homogênea artificial, isto é um metamaterial, que foi proposto por Smith e seus colaboradores [6-7]....
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...Os metamateriais descritos são bi-anisotrópicos e caracterizados por tensores permissividade e permeabilidade uniaxiais [7]:...
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...35 um material esquerdino bidimensional porque, mesmo que o E tenha que ser direcionado ao longo do eixo dos fios, duas direções são permitidas para o H , assim o [ε] não está carregado, contudo μxx < μyy para ω0m < ω < ωpm e μzz > 0 [7]....
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26 Sep 2011
TL;DR: A new structure of antenna with high gain is presented to improve the ability of DSRC system for the transportation system applications to use a metamaterial layer under a planar antenna.
Abstract: One of the most used systems in the toll domain is Dedicated Short Range Communication (DSRC) systems [1] where antenna is the most important part. It assures essentially the performance of wireless communication systems. Depending on each application, the directivity of the antenna is different. The higher antenna directivity is, the more effective system is. That is why there are increasing demands for designing this kind of antenna. This paper presents a new structure of antenna with high gain to improve the ability of DSRC system for the transportation system applications. The deal of the new antenna is to use a metamaterial layer under a planar antenna. Our great success is a perfect agreement between the real measured and simulated results with 16dBi of directivity.
2 citations
Cites methods from "Direct calculation of permeability ..."
...The layer based on metamaterial is designed by using SSRR (Square Split-Ring Resonator) elements (figure 5) [19] [20] [21] [22]....
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28 Nov 2012
2 citations
Cites methods from "Direct calculation of permeability ..."
...In these retrieval procedures, one cell thick sample in the propagation direction is assumed to be sufficient for effective parameter assignment due to electrically small cell size [56-60]....
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...There are a number of proposed analytical methods for the material parameter extraction in the literature [56-60]....
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TL;DR: In this paper, the use of resonating metamaterial unit cells in a single-layered non-optimized array between a number of ultrasound transceivers and targets was investigated.
Abstract:
Acoustic metamaterials have been proposed for numerous applications including subwavelength imaging, impedance matching, and lensing. Yet, their application in compressive sensing and imaging has not been fully investigated. When metamaterials are used as resonators at certain frequencies, they can generate random radiation patterns in the transmitted waves from the transducers and received waves from a target. Compressive sensing favors such randomness inasmuch as it can increase incoherence by decreasing the amount of mutual information between any two different measurements. This study aims at assessing whether the use of resonating metamaterial unit cells in a single-layered non-optimized array between a number of ultrasound transceivers and targets can improve the sensing capacity, point-spread function of the sensing array (their beam focusing ability), and imaging performance in point-like target detection. The theoretical results are promising and can open the way for more efficient metamaterial designs with the aim of enhancing ultrasound imaging with lower number of transceivers compared to the regular systems.
2 citations
22 Oct 2017
2 citations
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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