共查询到17条相似文献,搜索用时 140 毫秒
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提出了一种工作在C波段的新型平面结构异向介质,它除了带宽宽和损耗小外,还具有体积小、结构简单的优点,而且能够实现工作频段的平移,频率平移范围为4—20 GHz.基于电磁波由自由空间入射半无限大异向介质平板的传输和反射数据,计算出了电波在其中传播时的相速随频率的变化曲线,结果表明所讨论的异向介质确实在预想的频段上表现出后向波特性;同时利用相位观察法进一步验证了上述的后向波特性,从而肯定了异向介质的存在.
关键词:
异向介质
宽频带
小单元
后向波特性 相似文献
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基于DGS结构和双层SRRs结构,提出了一种工作于双频段的微带线结构的新型左手介质,它除了频带宽和损耗小外,还具有体积小、结构简单便于加工的优点. 基于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微带线的有效介电常数和有效磁导率,并进一步得到了电波在微带线上传播时的波数随频率的变化曲线,结果表明文中讨论的左手介质微带线确实在较宽的频段上表现出后向波特性,从而证实了左手介质的存在.
关键词:
左手介质
宽频带
电小单元
后向波效应 相似文献
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提出了一种基于TE10矩形波导的异向介质有效本构参数提取算法,利用该算法提取了对称多元胞铁氧体和金属线阵复合型异向介质的有效介电常数ε和有效磁导率μ.文中着重探讨了多元胞异向介质传播常数β实部的分枝选取问题,借鉴了测量理论中测量值和理论真值之间的关系,将单元胞的β提取值作为多元胞β的测量值,进而确定多元胞β的真实值;由于在多元胞异向介质各元胞之间存在耦合效应,使电磁波主要以周期性Bloch波的形式存在
关键词:
10矩形波导')" href="#">TE10矩形波导
异向介质
有效本构参数提取
铁氧体和金属线阵异向介质 相似文献
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基于负介电常数和负磁导率产生原理,采用金属细线和裂环谐振器结构,针对12.5 GHz频率开展双负媒质结构设计。通过特殊边界条件下S参数计算以及Nicolson-Ross-Weir方法,完成等效参数的提取,获得介电常数、磁导率、折射率实部均为负值,且折射率接近于0的左手材料特性。将双负媒质结构加载于Ku波段圆锥喇叭口面进行仿真优化,提高天线增益2.17 dB,在11~13 GHz频带范围内,加载天线的增益均有所改善。实验结果表明,口面加载双负媒质结构后,天线增益提高1.51 dB,后向辐射减小5.7 dB,辐射特性获得了明显改善。 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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Muhammad Rizwan Hai-Bo Jin Fida Rehman Zhi-Ling Hou Jing-Bo Li Faheem K. Butt Zulfiqar Ali 《Central European Journal of Physics》2014,12(8):578-581
This paper presents a negative refractive index tunable metamaterial based on F-Shape structure which is capable of achieving dual-band negative permeability and permittivity, thus dual-band negative refractive index. An electromagnetic simulation was performed and effective media parameters were retrieved. Numerical investigations show clear existence of two frequency bands in which permeability and permittivity both are negative. The two negative refractive index bandwidths are from 23.8 GHz to 24.1 GHz and from 28.3 GHz to 34.9 GHz, respectively. The geometry of the structure is simple so it can easily be fabricated. The proposed structure can be used in multiband and broad band devices, as the band range in second negative refractive index region is 7 GHz, for potential applications instead of using complex geometric structures and easily tuned by varying the separation between the horizontal wires. 相似文献
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Yong Zhi Cheng He Lin Yang Yan Nie Rong Zhou Gong Zheng Ze Cheng 《Applied Physics A: Materials Science & Processing》2011,103(4):989-994
A low losses broadband planar negative refractive index metamaterial based on split-ring resonator (SRR) pairs is proposed
and investigated experimentally and numerically at microwave frequency range. The transmission spectra of the single-layer
SRR pairs were measured, and exhibited left-handed (LH) transmission passband clearly. The metal-dielectric-metal structure
exhibits strong magnetic and electric responses simultaneously, and leads to negative permeability and negative permittivity.
To further verify the LH properties of planer structure metamaterials, effect media parameters were retrieved, a refraction
phenomenon based on a wedge-shaped model and negative phase advance between consecutive numbers of layers were also demonstrated. 相似文献
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Christian Imhof Remigius Zengerle 《Applied Physics A: Materials Science & Processing》2009,94(1):45-49
We report on microwave experiments with a metamaterial composed of pairs of metallic crosses. The transmission properties
of the structure show a left-handed transmission band at frequencies around 10.2 GHz. The validity of the negative effective
index of refraction is verified by a Snell’s law refraction experiment performed on a wedge-shaped sample of the metamaterial.
A second measurement of a similar wedge made from blank FR4 boards is done for reference. The results of the measurements
show positive refraction over the whole measured frequency band for the FR4 wedge as well as the refraction of the incident
radiation to negative angles within the designated left-handed frequency band for the metamaterial sample. 相似文献
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本文将磁谐振环-金属线共面结构与磁谐振环相结合, 提出了一种基于斜三角开口对环结构的新型宽频带低耗左手材料结构. 该结构能产生两个磁谐振, 实现两个双负频段. 研究表明, 调节单元尺寸可使两个双负频段移动重合形成一个宽频带. 理论分析、仿真和测试结果均表明, 本文提出的新形结构在9.3—13.2 GHz频段同时具有负的磁导率和负的介电常数, 相对带宽34.7%, 损耗性能系数347.9, 实现了宽带低耗左手材料. 其研究结果对多频段、宽带低耗左手材料的设计具有重要的指导意义. 相似文献
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Exploring electromagnetic response of tellurium dielectric resonator metamaterial at the infrared wavelengths 下载免费PDF全文
《中国物理 B》2015,(10)
We numerically investigate the electromagnetic properties of tellurium dielectric resonator metamaterial at the infrared wavelengths. The transmission spectra, effective permittivity and permeability of the periodic tellurium metamaterial structure are investigated in detail. The linewidth of the structure in the direction of magnetic field W x has effects on the position and strength of the electric resonance and magnetic resonance modes. With appropriately optimizing the geometric dimensions of the designed structure, the proposed tellurium metamaterial structure can provide electric resonance mode and high order magnetic resonance mode in the same frequency band. This would be helpful to analyze and design low-loss negative refraction index metamaterials at the infrared wavelengths. 相似文献
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The engineering in artificial inclusions of metamaterials has immense potential to explore in the field of electromagnetic wave manipulation that created enormous opportunities in the design of millimetre or sub-millimetres structures. In this research paper, Parabolic Split Ring Resonator (PSRR) based MNZ (Mu-Near-Zero) metamaterial with a wider refractive index is introduced for WiFi/WiMax/Wireless/ISM band applications and printing on Rogers RT-5880 lossy substrate with a copper-based metallic structure at 5.8 GHz within the microwave frequency region. The resonant frequency, negative permittivity, near-zero permeability, and negative refractive index are between 5.5-6.3 GHz. This proposed metamaterial structure is analysed with array structures, different substrate material, different orientations, and split gaps. 相似文献