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提出了一种新型二维左手材料结构单元,该结构由介质板及其两侧放置的两个反向对称的Z形金属条组成.在电磁波垂直于介质板和平行于介质板入射两种情况下,这种结构单元于X波段均表现出左手通带特性.通过模拟仿真,提取等效电磁参数,建立等效磁谐振电路模型,分析验证了该结构的左手特性.并将双Z形结构与相似的工字形结构相比较,发现在电磁波垂直入射时两种结构均出现相似的左手通带,而在电磁波平行入射时,只有双Z形结构实现了双负特性.结果表明这种双Z形左手单元结构具有更优越的电磁波入射适应特性,即实现了双入射型左手结构单元.
关键词:
双Z形结构
二维
左手材料
双入射 相似文献
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基于裂缝谐振环结构的降频技术,首先设计了一种电尺寸较小的左手介质微带线单元,并根据电磁波在微带线上的传输和反射数据,分别计算了左手介质的有效介电常数和有效磁导率.之后针对左手介质八元阵列进行三维电磁仿真实验,结果表明该八元阵列在左手介质频段上具有独特的后向波效应,从而证实了该左手介质频段的存在.与传统的左手介质微带单元相比,阐述的左手介质单元的电尺寸减小了60%,而且结构简单,便于加工,适用于平面电路器件的小型化等应用研究工作.
关键词:
左手介质
小型化
双负特性
后向波特性 相似文献
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基于裂缝谐振环结构的降频技术,首先设计了一种电尺寸较小的左手介质微带线单元,并根据电磁波在微带线上的传输和反射数据,分别计算了左手介质的有效介电常数和有效磁导率.之后针对左手介质八元阵列进行三维电磁仿真实验,结果表明该八元阵列在左手介质频段上具有独特的后向波效应,从而证实了该左手介质频段的存在.与传统的左手介质微带单元相比,阐述的左手介质单元的电尺寸减小了60%,而且结构简单,便于加工,适用于平面电路器件的小型化等应用研究工作. 相似文献
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通过设计一定的单元结构, 可以实现超宽带人工电磁材料. 基于蘑菇型金属结构, 提出了一种同时具有左右手通带无缝结合的超宽带双入射型复合媒质材料结构单元. 该结构由嵌入到介质板的两个反向对称的蘑菇型金属结构组成, 能够同时引发电谐振和磁谐振而得到左手通带. 通过利用CST软件仿真、等效电磁参数提取、折射率计算以及建立等效磁谐振电路模型等方法, 分析验证了该结构的双入射特性和左手特性. 仿真结果表明, 在电磁波垂直于介质板和平行于介质板入射两种情况下, 在X波段均表现出左手通带特性, 并具有1 GHz以上的左手带宽. 当电磁波垂直于介质板入射时, 在7.2 GHz-9.3 GHz频段为右手通带, 在9.3 GHz-11 GHz频段为左手通带; 当电磁波平行于介质板入射时, 在7.0 GHz-9.0 GHz频段为右手通带, 在9.0 GHz-10 GHz频段为左手通带. 在两种情况下分别于9.3 GHz与9.0 GHz处得到了零折射率, 从而构造了一种正-零-负复合媒质材料, 实现了具有3 GHz带宽的双入射超宽带平衡结构. 相似文献
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由均匀平面电磁波在左右手媒质界面满足的切向边界条件出发,推导了电磁波由线性传统媒质入射到非线性左手媒质时波的传播特性.利用时间延迟的方法,给出全反射情况下媒质界面非线性Goos-Hǎnchen位移表达式.分析了非线性左手媒质界面的侧向位移随入射角及入射波电场强度的变化关系,发现入射波场强对传输特性起决定作用:当入射波电场小于临界场强时,调节入射场强可以控制相应的侧向位移;当入射波电场大于临界场强时,不再满足全反射条件,部分入射波透射到非线性介质中.波导中加入非线性介质不仅可以调节侧向位移的大小,且可以实现对入射波场强的控制. 相似文献
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In this present communication, we study the reflection behavior of electromagnetic in one-dimensional photonic crystal of electromagnetic waves in microwave region of electromagnetic spectrum. The Plasma Photonic Crystal structure is composed of alternate layers of thin micro-plasma and dielectric material electromagnetic (EM) spectrum in one-dimensional Plasma Photonic Crystals (PPCs). In order to obtain the characteristic equation (dispersion relation), we have solved the Maxwell scalar wave equation. Beside this we study the anomalous behavior of group velocity and effective index of refraction of PPCs in microwave region. We have adopted Transfer Matrix Method (TMM) for calculating reflectance and dispersion relation of PPCs. In order to calculate the expression for effective refractive index inside the PPCs structure we have used the concept of the group velocity instead of phase velocity. 相似文献
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Cumali Sabah 《Central European Journal of Physics》2008,6(4):872-878
In this work, the concept of left-handed chiral metamaterials is analyzed by emphasizing their optical ability on the rotation
of the plane of polarization of a wave. The possibilities of a negative phase velocity, negative and positive propagation
constants, and basic electromagnetic properties of this novel medium are also presented. After the characterization of left-handed
chiral metamaterial, we provide a reflection and transmission study for two planar boundaries of nonchiral-left-handed chiral
metamaterial for normal angles of incidence. Some numerical results are also provided to validate the formulation found in
the analysis and to show the role of the chirality in the propagation constants, phase velocities, reflection and transmission.
相似文献
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左手系材料界面上的非线性TE电磁波 总被引:4,自引:4,他引:0
针对电磁波在非线性左手系材料中的传播性质, 分别研究了左、右手系材料界面以及两左手系材料界面上非线性TE表面波的传播行为讨论了导波的频率特性、色散关系以及群速度随频率的变化规律分析表明,两种界面上的非线性TE表面波均存在频率通带和禁带,且带宽是传播功率的函数揭示了在一定条件下,左、右手系材料界面上既可以支持正向传播的非线性TE表面波,也可以支持反向传播的非线性TE表面波;两左手系材料界面上表面波的传播性质因材料参量的变化差异较大,一定参量条件下,该界面上仅支持反向传播的非线性TE表面波. 相似文献
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LIN Qiong-Gui 《理论物理通讯》2006,45(5):919-922
In quantum mechanics the center of a wave packet is precisely defined as the center of probability. The center-of-probability velocity describes the entire motion of the wave packet.
In classical physics there is no precise counterpart to the
center-of-probability velocity of quantum mechanics, in spite of the fact that there exist in the literature at least eight different velocities for
the electromagnetic wave. We propose a center-of-energy velocity to
describe the entire motion of general wave packets in classical
physical systems. It is a measurable quantity, and is well defined
for both continuous and discrete systems. For electromagnetic wave
packets it is a generalization of the velocity of energy transport.
General wave packets in several classical systems are studied and the
center-of-energy velocity is calculated and expressed in terms of the
dispersion relation and the Fourier coefficients. These systems
include string subject to an external force, monatomic chain and
diatomic chain in one dimension, and classical Heisenberg model in
one dimension. In most cases the center-of-energy velocity reduces to
the group velocity for quasi-monochromatic wave packets. Thus it also
appears to be the generalization of the group velocity. Wave packets
of the relativistic Dirac equation are discussed briefly. 相似文献
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Phase and group velocities of plane waves may have different directions in a linear and homogeneous medium. This difference may lead to interesting situations such as the phase reversal propagation and the orthogonal phase velocity. Although the former has been analyzed in depth and it has found many applications, the latter has been left as a hypothesis. Actually, due to our best knowledge there is no evidence of such media where the phase velocity is orthogonal to the group velocity. In this paper we discuss this situation thoroughly. We show that a plane wave with orthogonal phase velocity cannot possess linear momentum. Moreover, we show that a plane wave without the linear momentum cannot propagate at all, so the orthogonality of the phase velocity does not take place in reality for electromagnetic plane waves. 相似文献
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M. V. Davidovich 《Technical Physics》2010,55(5):630-635
The simplest dispersion relation determined by dissipation due to conduction is considered; the electromagnetic energy density
in a plane monochromatic wave and its (phase and group) velocity are determined, as well as the energy and momentum transfer
rates. It is shown that the energy density at low frequencies in this case has the form of the electrostatic density, in which
the permittivity is replaced by its real part, and the energy transfer rate in a plane electromagnetic wave is equal to the
phase velocity. The group velocity may exceed the speed of light. 相似文献
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Starting from the concept of rapidity considered as generalization of the group velocity, we establish a generalized mathematical expression for the refractive group index of a material medium with little refraction at sufficiently small wavelengths, this index becoming approximately the refractive index at the geometric-optics limit and the phase velocity being approximately equal to the group velocity at the above limit. As main result, we derive an approximate relationship for the refractive index of a medium of small refraction at the geometric-optics limit. This medium is found to be left-handed at sufficiently small wavelengths. 相似文献
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We present the first treatment of the refraction of physical electromagnetic waves in newly developed negative index media (NIM), also known as left-handed media (LHM). The NIM dispersion relation implies that group fronts refract positively even when phase fronts refract negatively. This difference results in rapidly dispersing, very inhomogeneous waves. In fact, causality and finite signal speed always prevent negative wave signal (not phase) refraction. Earlier interpretations of phase refraction as "negative light refraction" and "light focusing by plane slabs" are therefore incorrect, and published NIM experiments can be explained without invoking negative signal refraction. 相似文献
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We study the electromagnetic surface wave localizing, the so-called surface Tamm states, at an interface separating a left-handed metamaterial (LHM) and a semi-infinite one-dimensional photonic crystal made of alternative left-handed metamaterial and right-handed materials. We show that the existence of metamaterial causes the Tamm states with backward energy flow and allows flexible control of dispersion properties of the surface modes. We study the effect of the physical parameters of the photonic crystal on the dispersion properties and the group velocity of the Tamm states. We also study dispersion properties of the Tamm states in higher order photonic band gaps of the photonic crystal and compare our results with the case when the LHM medium is replaced by a right-handed material (RHM). 相似文献
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Riyopoulos S 《Optics letters》2006,31(16):2480-2482
It is shown that the boundary conditions at left-handed material interfaces cause reversal in the propagation direction of the parallel-to-the-surface electromagnetic energy and momentum fluxes. First-principle examination excludes the possibility of induced surface wave excitation as a way of providing radiation momentum conservation. Thus the imparted net change in electromagnetic momentum should cause a recoil force parallel to the surface, which is unique to left-handed interfaces. The shear force exerted on a left-handed material interface is computed. The magnitude of this force is found detectable by experiments. 相似文献