共查询到19条相似文献,搜索用时 203 毫秒
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利用碳纳米管在外加静电场下可产生常温太赫兹频段负微分电阻的特性, 提出了太赫兹波频段的有源超材料设计方法以及块状有源超材料等效电磁特性参数提取方法. 对无源金属线阵进行参数提取, 证明所提出的块状有源超材料等效电磁特性参数提取方法, 可以有效解决传 统参数提取中的符号与多分支选择问题. 通过对嵌入具有负微分电阻特性的碳纳米管的金属线阵进行参数提取, 发现太赫兹波有源超材料不仅具有等效介电常数虚部为负(代表电有源)的特性, 而且还具有磁性色散的特性. 相似文献
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研究了负折射率材料对产生Casimir排斥效应的影响. 两材料板间的Casimir排斥力的发生取决于两板以及其间媒质的电磁特性,通过理论与数值结果的分析研究给出电磁特性所影响排斥力的产生趋势. 对于由Drude-Lorentz型色散关系描述等效介电常数和磁导率的负折射率材料,调节各特征频率参数可实现Casimir排斥效应.
关键词:
Casimir排斥力
负折射率材料
Drude-Lorentz型色散关系 相似文献
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用矩形波导法实验研究了微波垂直入射于具有一定厚度的金属铜圆环结构的微波电磁响应行为.结果表明,当金属铜环的厚度增加到一定值时,在中心频率为145GHz处出现透射禁带,并且相位在透射禁带处发生跃变.采用双各向异性媒质理论计算了铜圆环结构的磁导率随频率变化关系,在透射禁带处磁导率为负.对厚金属圆环与金属线一一对应组合的样品,微波沿环面垂直入射时测量到左手透射通带和相位超前,通带带宽达到15GHz,强度为-21dB.
关键词:
负磁导率
垂直入射 相似文献
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A new quantum optical mechanism to realize simultaneously negative
electric permittivity and magnetic permeability is suggested. In
order to obtain a negative permeability, we choose a proper atomic
configuration that can dramatically enhance the contribution of the
magnetic-dipole allowed transition via the atomic phase coherence. It
is shown that the atomic system chosen with proper optical parameters
can give rise to striking electromagnetic responses (leading to a
negative refractive index) and that the atomic vapour becomes a
left-handed medium in an optical frequency band. Differing from the
previous schemes of artificial composite metamaterials (based on
classical electromagnetic theory) to achieve the left-handed
materials, which consist of anisotropic millimetre-scale composite
structure units, the left-handed atomic vapour presented here is
isotropic and homogeneous at the atomic-scale level. Such an
advantage may be valuable in realizing the superlens (and hence
perfect image) with left-handed atomic vapour. 相似文献
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根据周期性细导线阵列结构的等效电路模型,从电介质材料的本构关系出发,推导出细导线阵列结构的等效介电常数的表达式,并从电场强度与电极化强度之间的相位关系,说明在特定的入射电磁波频段,它的等效介电常数为负. 相似文献
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A composite medium consisting of two sublattices of dielectric spherical particles of high permittivity and different radii
embedded in a dielectric matrix of smaller permittivity are considered. It has been shown that such a composite medium reveals
properties of an isotropic double negative media (DNG) in a limited frequency range, when resonance oscillations of HIII mode in one kind of particles and EIII mode in another kind of particles are excited simultaneously. The EIII resonance and the HIII resonance give rise to the magnetic dipole momentum and the electric dipole momentum correspondingly. Averaging the magnetic
momentum and the electric momentum over the cells belonging to the appropriate spherical particles gives the negative permittivity
and permeability. The model of diffraction of a plane electromagnetic wave on a dielectric sphere is presented and compared
with the mixing rule based consideration. The results obtained are rather close. Distribution of the electromagnetic wave
outside the sphere is calculated. Influence of the dispersion of the sphere size and the dielectric permittivity on the effective
parameters of the DNG material is estimated. 相似文献
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Experimental study of composite medium with simultaneously negative permeability and permittivity 总被引:1,自引:0,他引:1
SUI Qiang & LI Fang . Institute of Electronics Chinese Academy of Sciences Beijing China . School of Information Beijing Broadcasting Institute Beijing China Correspondence should be addressed to Sui Qiang 《中国科学G辑(英文版)》2004,47(1):64-78
Inclassicalelectrodynamics,theresponse(typicallyfrequencydependent)ofamaterialtoelectricandmagneticfieldsischaracterizedbytwofundamentalquantities,thepermittivityeandthepermeabilitym.Bothmandearepositiveinmostmaterials.In1968,Veselago[1]predictedthattheelectromagneticwavepropagationinamediumhavingsimultaneouslynegativepermittivityandpermeabilityshouldgiverisetoseveralpeculiarcharacteristics.Butnoneofhispredictionsweretestedduringthelastcentury,becausenonaturalmaterialswithsimultaneouslynegativ… 相似文献
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Koray Aydin Zhaofeng Li Serafettin Bilge Ekmel Ozbay 《Photonics and Nanostructures》2008,6(1):116-VII
We report on the transmission properties of the omega (Ω) type metamaterials. Transmission through the periodic Ω-only and Ω-wire metamaterials are studied experimentally and numerically. A resonance band gap is observed for the periodic Ω medium around the resonance frequency of the single Ω unit cell. A transmission band is observed below the resonance band gap, when the periodic Ω structure is embedded in a negative permittivity medium composed of thin metallic wire arrays. We also studied the effect of periodicity on the transmission spectra of Ω type metamaterials. 相似文献
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The design of the metamaterial that can exhibit negative refraction at two frequency bands is presented. The components of this metamaterial are cut wire pairs and continuous wires. The cut wire pairs structure in our sample can achieve the magnetic resonance at two frequency bands by appropriately designing the cut wire dimension. Through numerical simulation, the transmission property of the proposed dual band negative index metamaterial is investigated and its result shows that with the introduction of continuous wires, the stop bands for cut wire pairs (permeability μ<0) and the frequency band for continuous wires (permittivity ε<0) components would overlap and lead to the appearance of pass bands near the two magnetic resonance frequency bands. Its electromagnetic properties are then retrieved to demonstrate that the dual band left-hand behavior can be obtained in our sample structure. It is believed that our approach will be effective to make this kind of dual band negative refractive metamaterial based on the multiple magnetic resonances work at optical frequency. 相似文献