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建立了一般性二维分布网络的标量波动方程,导出了二维分布网络的电压分布、电流分布、x方向和z方向阻抗以及传播常数,并把这些结果应用到二维加载L,C传输线媒质(负折射率媒质)和未加载传输线媒质(正折射率媒质).获得加载传输线媒质的物质参数并显示为负数.利用这些表达式采设计这两种媒质的电参数和适当的平面波激励,利用微波电路对入射角为60°的平面电压波入射到相对折射率为一<平方根3>的正负传输线媒质界面上进行仿真.仿真结果显示,在界面上发生了负折射,从而验证了本推导公式的正确性. 相似文献
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给出由负折射媒质构成的球形天线罩包围的垂直电偶极子在空间辐射的电磁场解析表达式.讨论了偶极子的位置与球形天线罩材料的电磁特性对辐射场的影响.理论分析和计算结果表明:当偶极子位于球心时,辐射的电磁场和文献[8]的结果吻合很好;随着场点与球心距离的增加,偶极子的放置位置对辐射场影响变小;相对于普通介质和自由空间,负折射媒质构成的球形天线罩增强了垂直偶极子的空间辐射特性. 相似文献
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人为制造一种具有负介电常数ε和负磁导率μ的媒质,即所谓"负折射率"媒质(或称为"左手媒质"LHM)已成为目前研究的一个热点."中国科学"(G辑)2003年第33卷第5期"负介电常数和负磁导率微波媒质的实验"一文用实验方法验证了该类媒质的存在,在国内尚属首次.纵观全文有两点疑问,有必要提出来以推动该项研究. 相似文献
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讨论高斯波包激励的垂直电偶极子在由介电常数和磁导率都为负数的介质和普通介质组成的均匀半空间中产生的瞬态磁场,得出了它的近似解析表达式.理论分析和数值计算表明:当二种介质中有一种是负折射媒质时,磁场分量的时域场除了分别沿两种媒质一侧传播的侧面波波包外,还存在表面波波包.此种表面波波包对任一场点处磁场的贡献比两种均匀媒质中传播的侧面波包的贡献大. 相似文献
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Design, fabrication, and testing of double negative metamaterials 总被引:16,自引:0,他引:16
The design, fabrication, and testing of several metamaterials that exhibit double negative (DNG) medium properties at X band frequencies are reported. DNG media are materials in which the permittivity and permeability are both negative. Simulation and experimental results are given that demonstrate the realization of DNG metamaterials matched to free-space. The extraction of the effective permittivity and permeability for these metamaterials from reflection and transmission data at normal incidence is treated. It is shown that the metamaterials studied exhibit DNG properties in the frequency range of interest. 相似文献
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张玲芬 《太赫兹科学与电子信息学报》2006,4(3):212-214
为了研究负折射率介质这种新型复合材料的电磁性质,利用麦克斯韦电磁理论对电磁波在正、负折射率介质交界面上的反射和透射特性进行了分析。得到了Snell反射定律和折射定律,反射系数和透射系数随入射角的关系(Fresnel公式)。结果发现Snell反射定律和折射定律仍然适用。但折射线与入射线位于法线的同侧;不论是腰波还是TM波,当以某一入射角入射时,反射系数都有可能变为零。这些结果对于设计新型的电磁学和光学器件具有指导性的意义。 相似文献
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建立了可调谐双耦合场作用下的A型四能级系统模型,研究了系统的介电常数和磁导率随耦合场参数的变化规律,并由此探讨了满足负折射的条件.结果表明,固定耦合场的拉比频率,当两个耦合场中的一个共振、另一个失谐,或两个耦合场均失谐时满足负折射条件,但它们呈现不同的负折射特性. 相似文献
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Planar negative refractive index media using periodically L-C loaded transmission lines 总被引:44,自引:0,他引:44
Recent demonstrations of negative refraction utilize three-dimensional collections of discrete periodic scatterers to synthesize artificial dielectrics with simultaneously negative permittivity and permeability. In this paper, we propose an alternate perspective on the design and function of such materials that exploits the well-known L-C distributed network representation of homogeneous dielectrics. In the conventional low-pass topology, the quantities L and C represent a positive equivalent permeability and permittivity, respectively. However, in the dual configuration, in which the positions of L and C are simply interchanged, these equivalent material parameters assume simultaneously negative values. Two-dimensional periodic versions of these dual networks are used to demonstrate negative refraction and focusing; phenomena that are manifestations of the fact that such media support a propagating fundamental backward harmonic. We hereby present the characteristics of these artificial transmission-line media and propose a suitable means of implementing them in planar form. We then present circuit and full-wave field simulations illustrating negative refraction and focusing, and the first experimental verification of focusing using such an implementation. 相似文献
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圆偏振光在手征负折射材料表面的反射和极化特性研究 总被引:2,自引:1,他引:1
从理论上分析了圆偏振光入射到手征负折射材料表面的反射与透射特性,给出了归一化反射透射功率与入射角的关系曲线以及布儒斯特角与手征参数之间的关系曲线.当入射角大于两个本征波的临界角时,全内反射现象发生.由于手征负折射介质中的一个本征波发生了负折射,右旋或左旋圆偏振光入射时反射波的极化态有着与常规介质完全不同的特性,以布儒斯特角入射时反射光都为线偏振波但极化方向并不相同. 相似文献
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A new planar metamaterial (MTM) with simultaneous negative values of permittivity (ε) and permeability (μ) is proposed. Our MTM is composed of two identical copper patterns etched on both sides of dielectric laminate, which is very thin and easy to fabricate. Unlike conventional MTMs, the proposed structure shows a negative refractive index (NRI) behavior with respect to a normally incident wave. To explain the underlying principle of the NRI characteristics, an equivalent resonant circuit model based on surface current density distribution is investigated. An eigenmode analysis and a three‐dimensional wave simulation for the stacked MTM prism are also performed to verify the existence of negative refraction. The experimental results from the transmission and reflection measurement ensure the validity of our design approach and show good agreement with the theoretically predicted effective medium parameters. 相似文献
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Xiangxiang Cheng Hongsheng Chen Bae-lan Wu Jin Au Kong 《Antennas and Propagation Magazine, IEEE》2009,51(4):79-87
Chiral nihility media are known to produce a backward wave as one of their two polarizations, yielding negative refraction at the interface of the chiral nihility medium and free space. In this paper, the analysis of chiral nihility effects is illustrated by showing the propagation of a Gaussian beam, both reflected and refracted from an air-chiral interface, and through layered chiral nihility media that are matched to free space. The critical angle for total reflection, and the index-matched total transmission in a matched chiral half-space, are demonstrated. Also demonstrated are the wave splitting, wave widening, and a wave of “standing phase” in matched chiral nihility slabs. 相似文献
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介绍了一种具有两个通带的新型混合左右手传输线,以及混合左右手材料传输线的传输特性和分析方法。该左手材料(Left-Handed Metamaterials,LHMs)在通带内呈现介电常数和磁导率同时为负的特性,两个通带分别出现在2.8 GHz和5.8 GHz处。通过仿真得到了色散曲线,折射率,等效介电常数和等效磁导率,从理论上验证了左手特性的存在。 相似文献