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为了克服微带天线的横向尺寸需要满足半个波长的限制,本文提出了一种基于复合左右手传输线技术的二元阵天线.该天线阵由结构相同的两个天线阵单元构成:天线阵单元由3个辐射片、辐射片之间的交指电容和导通辐射片和接地板的短路针组成.辐射片、短路针、天线阵的基片和接地板构成了复合左右手传输线结构.天线阵单元之间通过弓形连接线连接,通过调节弓形连接线两个端口到馈源之间的距离来调节天线阵单元之间的初始相位差.在关心频段内,数值计算得到的二元阵天线的S参数与实际测量结果符合得很好,并且零阶谐振频率与用等效电路理
关键词:
天线
异向介质
左右手传输线
增益 相似文献
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基于电谐振原理和镜像原理设计了一种周期性接地边耦合SRRs(split ring resonators)结构的新型电谐振人工异向介质,进而将该人工异向介质应用于抑制微带阵列天线元间的互耦.与传统微带阵列天线中的用于抑制互耦的电磁结构相比,该人工电磁结构不仅体积小(厚度仅为0·005λ0),而且能获得优异的阵列单元间互耦抑制性能(抑制度达16·8dB).该研究成果表明人工异向介质在高密度高性能微带天线阵列设计中具有良好的应用潜能. 相似文献
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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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针对通信与雷达系统对双极化与宽带天线的要求,提出了一种基于带状线馈电的双极化蝶形天线。通过两对互相正交的蝶形阵子实现了天线的双极化,并采用一种新型的微带线转异面带状线的巴伦给两对正交蝶形阵子平衡馈电。异面带状线为平衡传输线,满足了蝶形阵子对于平衡馈电的要求。在馈电点处由同轴线对微带线馈电,经渐变微带线转化为异面带状线,最后由两组异面带状线给两对正交蝶形阵子馈电。测得该天线实现了69.23%的阻抗带宽,在6.8~14GHz频带内电压驻波比(VSWR)小于2。为使天线单向辐射且改善天线增益,将天线放置于反射吸收腔内。测得天线在6.8~18GHz的频宽内VSWR基本小于3,天线增益在8~12GHz频带内大于0.11dB,天线前后瓣比大于15dB。因此,所提出的双极化蝶形天线可用于宽带通信系统中。 相似文献
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提出一种单元电尺寸小、工作频带宽、损耗小、结构简单的异向介质设计方案,在1.7—2.7 GHz上所设计的异向介质结构单元电尺寸小于0.035,相对带宽达到45.5%,在整个工作频带上单个结构单元传输损耗小于0.75 dB.对由上述异向介质单元构成的半无限大异向介质平板的电磁波反射、透射特性进行了数值仿真分析,并提取出了电磁波在该异向介质平板中传播时的波数、相速、折射率以及该异向介质平板的有效介电常数和有效磁导率等一系列电磁特性参数,仿真与计算结果表明复波数的实部、相速以及折射率的实部在1.7—2.7 GHz的范围上为负值,并且在相同频带上,有效介电常数和有效磁导率的实部同时为负值,从而有效地验证了“后向行波效应”、“负折射效应”、“双负效应”等异向介质特有的电磁特性,对上述异向介质的存在性给予有力证明.
关键词:
异向介质
宽频带
小单元
介质参数 相似文献
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设计了一款基于共面波导馈电的小型化具有双陷波特性的超宽带天线,该天线的带宽在3~14 GHz内,电压驻波比(VSWR)小于2。在辐射贴片上通过开L型和半圆环缝隙实现了在3.3~3.7 GHz和5.150~5.825 GHz的双频段的陷波特性,抑制了802.16无线城域网和无线局域网对超宽带系统的干扰,在整个工作频段具有稳定的增益和良好的全向性。通过对天线模型进行加工制作并测量,测试结果表明:天线的带宽是3~14 GHz,在3.3~3.7 GHz和5.15~5.825 GHz频段内VSWR大于4,实现了天线的双陷波特性。该天线尺寸小、结构紧凑的特点,适合现代的无线通信系统。 相似文献
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基于液晶材料(LC)的双折射特性提出了一种基于液晶材料的短十字型阵列电控超材料,超材料包括了上层石英板,金属结构阵,中间液晶介质层,金属地板以及下层石英板。相比于传统的阵列天线设计,运用了新的相位补偿方法,即通过加电改变反射阵列单元的介质基板液晶的介电常数得到的相位曲线实现0~250°的相位补偿,使得超材料实现在U波段的相位变化。仿真结果表明,通过将偏压从0增加到14 V,超材料在52 GHz时呈现250°的相移。此外,此超材料的谐振频率可从53.6 GHz连续可逆地转移到49.9 GHz。通过调节超材料液晶激励区域的介电常数即改变阵列单元的谐振特性,实现了相位补偿,为平面反射阵列天线的设计提供了一种新思路。 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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A tunable broadband metamaterial absorber is demonstrated at microwave frequencies in this paper.The metamaterial absorber is composed of ferrite slabs with large resonance beamwidths and a copper wire.The theoretical analysis for the effective media parameters is presented to show the mechanism for achieving the perfect absorptivity characteristic.The numerical results of transmission,reflectance,and absorptivity indicate that the metamaterial absorber exhibits a near perfect impedance-match to free space and a high absorptivity of 98.2% for one layer and 99.97% for two layers at 9.9 GHz.The bandwidth with the absorptivity above 90% is about 2.3 GHz.Moreover,the absorption band can be shifted linearly in a wide frequency range by adjusting the magnetic bias.This metamaterial absorber opens a way to prepare perfectly matched layers for engineering applications. 相似文献
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本文设计了一种基于开口谐振环(split ring resonator, SRR)混合排列单元格的小型化双频带超材料(metamaterial, MM). 该MM的单元结构为发卡式SRR, 所设计的双频带MM可以应用于无线局域网(2.4 GHz) 和全球微波互联接入(3.5GHz)系统. 并且, 采用柔性介质作为基板增加了MM的柔韧度和普适性, 实验和测试结果表明: 双频带MM的中心频率可以通过调节SRR的尺寸进行控制. 此外, 本文也对MM在不同入射角的情况进行了分析, 结果表明MM对入射角度不敏感.最后, 通过MM的表面电流分布情况研究, 进一步解释了其双频带谐振频率的产生原理. 相似文献
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The research aims to develop a more sophisticated novel left-handed and compact square-shaped metamaterial (SM) inspired multi-frequency bands like C-, X- and Ku-band applications. Even though the performance of existing satellite application devices are adequate, significant changes in technology over the past decades require advanced and more accurate techniques or devices. Hence, we approach the problem with a broader perspective by integrating a metamaterial structure in satellite application devices. As a general rule, the unconventional material known as metamaterial has extraordinary electromagnetic properties which are impracticable in commercially available materials. It represents an important study topic because this type of peculiar material is generally used in many field applications which encouraged us to experiment with the stated frequency bands by introducing a novel SM design. The novel SM design structure involved a 1.6 mm Epoxy Resin Fibre (FR-4) substrate material. This compact metamaterial design contains nine square rings with an altered small square ring joined in it. The numerical simulation of the SM design for satellite frequencies was performed using the Computer Simulation Technology (CST) Microwave Studio. The scattering parameters of the suggested SM design were determined by utilising Finite Integration Technique (FIT) in CST software. Several parametric studies that were analysed in this study include various design structure, types of substrate materials and SM array arrangement. Based on the adapted simulated frequency range (4 to 18 GHz), the unit cell SM exhibited five resonance frequencies at 5.49 and 7.33 GHz (in C-Band), 9.05 and 11.38 GHz (in X-Band) and 13.48 GHz (in Ku-Band). The measured resonance frequencies of the unit cell were 5.62 and 7.39 GHz (in C-Band), 9.15 and 11.32 GHz (in X-Band) and 13.51 GHz (in Ku-Band). The resonance frequencies obtained from both methods were similar. According to all three resonance frequencies, the SM design manifested a left-handed characteristic. Hence, on this basis, the proposed SM design with unique characteristics is deemed suitable for C-, X- and Ku-bands applications. 相似文献
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Huiliang Xu Zeyu Zhao Yueguang Lv Chunlei Du Xiangang Luo 《International Journal of Infrared and Millimeter Waves》2008,29(5):493-498
A high directive planar antenna made from a metamaterial superstrate and an electromagnetic band-gap (EBG) substrate has been
investigated. A patch antenna surrounded with EBG structures is used as the radiation source. The CST Microwave Studio is
used for the simulation. The results show that the gain of the antenna with metamaterial is 21.6 dB at the operating frequency
of 14.6 GHz. Compared with the patch feed with the same aperture size but without the metamaterial superstrate, the performance
of the antenna is improved obviously and the gain increases about 12.4 dB. 相似文献
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仿真并实验验证了基于电磁谐振的极化无关透射吸收超材料吸波体, 该吸波体可以实现低频透射和高频吸收.实验测试结果表明, 该吸波体在6.77 GHz 吸收率峰值为83.6%, 半功率带宽为4.3%, 实现窄带强吸收.为进一步拓展该谐振型超材料吸波体的吸收带宽, 利用其低频透射特性, 将两个工作于不同频段的吸波体叠加在一起, 测试结果表明, 复合后超材料吸波体的半功率带宽可以增大到10.9%, 吸收率也略有增强. 该超材料吸波体设计简单, 具有较强的实用性和应用前景.
关键词:
极化无关
透射吸收
超材料吸波体 相似文献
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The research of high-directive anisotropic magnetic metamaterial antenna loaded with frequency-selective surface
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This paper uses a Computer Simulation Technology microwave studio to
simulate the performance of a new high-directivity anisotropic
magnetic metamaterial antenna loaded with a frequency-selective
surface. Frequency-selective surface with cross-dipole element has a
great effect on the directivity, radiation pattern, and gain of such
an antenna. The experimental results show that frequency-selective
surface (FSS) significantly improve the radiation performance of
anisotropic magnetic metamaterial antenna. For example, as a single
anisotropic magnetic metamaterial antenna, half power beam width is
4 degrees in the H planes, and the gain of this antenna is 19.5 dBi at
10 GHz, achieving a 2.1 degree increment in half power beam width,
and a 7.3 dB gain increment by loading with the FSS reflector. The
simulating results are consistent with our experimental results. 相似文献
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为了缩减天线带内雷达散射截面(radar cross section, RCS), 在双频带完美吸波材料的基础上, 通过缩小两吸波率峰值之间的距离, 设计出了一种频带较宽的超薄完美吸波体.该吸波体由两层金属及其中间的有耗介质组成, 底面金属不刻蚀, 顶面由方形贴片和绕其四周的开口方环组成, 该结构具有低频点LC谐振和高频点偶极子谐振的特征.仿真和实验结果表明: 该吸波体具有极化不敏感和宽入射角的特征, 其在厚度小于0.01λ的条件下, 具有8.2%的半波功率相对带宽, 最大吸波率的峰值为91.6%和96.5%. 将吸波体用于圆极化的倾斜波束 (tilted beam, TB)天线, 仿真和测试结果表明: 该天线在保持增益不变的条件下, 不仅轴比得到改善, 有效带宽得到拓展, 且在5.5–6.5 GHz范围内TB天线的RCS缩减至少在3 dBsm以上, 在谐振频点处最大缩减幅度分别为11 dBsm和8 dBsm; 在两谐振点处鼻锥方向-36°–+36°范围内, TB天线的RCS缩减均有明显效果.
关键词:
超薄完美吸波体
TB天线
雷达散射截面
圆极化 相似文献