共查询到19条相似文献,搜索用时 875 毫秒
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《无线电工程》2018,(1):55-58
针对移动通信对天线小型化的需求,提出了一种基于左手材料实现微带天线小型化的方法。在谐振频率为5.8 GHz的微带天线的接地板上蚀刻圆形单开口谐振环(Circular Split Single-Ring Resonator,CSSRR)结构的左手材料,利用左手材料的后向波特性进行相位补偿,打破传统微带天线半波长电尺寸的束缚,从而达到天线小型化的目的。采用Ansoft HFSS软件进行仿真,分析了CSSRR结构的电磁特性和小型化天线的性能。仿真结果表明,小型化天线与传统微带天线相比辐射贴片的尺寸减小37.52%,带宽略有增加,增益等参数性能基本保持不变。而且该小型化微带天线结构简单,易于实现。 相似文献
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设计出一种由两个六边形开口谐振环组成的电磁超材料单元,这种新型的电磁超材料单元实现了左手特性。然后优化出一个中心频率为16 GHz的二元阵列微带天线,将左手材料单元置于辐射贴片周围,利用三维电磁仿真软件HFSS对其进行优化仿真,最终制作了一款加载左手材料的微带阵列天线。仿真及实测结果表明,在相同的工作频率下,加载了左手材料的阵列天线与普通阵列天线相比,其谐振点的回波损耗由-32.7 dB减小到-59.7 dB,同时在低频产生了谐振点,实测其旁瓣得到了有效的缩小,主瓣变窄,方向性增强,增益由8.3 dB增加到8.8 dB,提高了天线的多项性能指标,且实测回波损耗与仿真曲线吻合较好,在16 GHz处的增益图与仿真对比大致相同。 相似文献
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用左手材料设计一种宽频带并且电尺寸小的微带天线,先用开口谐振环和金属杆设计出左手材料,并把它放在微带天线的基板中,利用左手材料的相位补偿特性实现了宽带微带天线的小型化设计。数值仿真结果表明,工作于10.5GHz时,加载了左手材料的微带天线的物理尺寸被大大减小了,天线尺寸从下降到0.21λ,突破了传统微带天线的半波长限制,并且相对带宽增加了5.31%,实现了微带天线的小型化设计。 相似文献
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介绍和分析了左手介质的构造原理和方法,通过对加载左手介质材料的贴片天线的研究,来说明左手介质天线的一些优异特性。仿真和实测结果表明,通过加载左手介质材料,普通贴片天线会产生新的特性,如工作频率的降低、天线增益的提高、方向性的增强等。而且,天线的物理尺寸能得到很大的减小,这就为高增益、高带宽的小型化贴片天线设计提供了新的方法和思路。 相似文献
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为研究电磁波在有损耗左手材料中的传播特性,采用时域有限差分(FDTD)法和色散媒质的Drude模型,推导出基于Drude模型的左手材料二维FDTD迭代方程。一维数值仿真结果验证了平面电磁波在穿过有耗左手材料时,其相速度大小与光速相同,方向与传播方向相反,且随着损耗因子的增大,左手材料内的电场强度幅值亦相应减小。此外,还利用多循环m-n-m脉冲作为激励源,对左手材料平板具有的完美透镜现象进行了二维数值仿真验证。结果表明,有耗平板左手材料具有明显的聚焦效果,在特定条件下能实现完美成像。 相似文献
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A high-T c superconducting (SC) active antenna with a corner reflector is found to be useful for detecting electromagnetic waves (f =9.55 GHz). The SC active antenna is a new type of antenna which consists of material properties and antenna properties. The microwaves with fixed polarizations are radiated to the SC active antennas, and the detectivities and the directivities were confirmed experimentally. With the use of the corner reflector, the sensitivity and the directivity can be improved 相似文献
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用等离子体代替金属制作天线进行信号发射与接收,其应用范围十分广泛,但常规等离子体天线采用硬质玻璃管或石英管构建,易受损且难以改变形状。文中提出采用常用软质真空管结合气体放电,激励电源、馈电、屏蔽、耦合装置等构建等离子体线天线。改变放电功率和天线形状,可使天线的通信频带范围从100 MHz 调节到300 MHz,3 dB 增益带宽最大达100 MHz以上,与相同形状的常规等离子体天线相比,性能相差不大。同时,该天线不仅可以实现阻抗、方向性的动态重构,也能够满足左旋圆极化、右旋圆极化转化的需求。该研究可以为实现与优化可重构等离子体天线、以及在航空、航海等军民融合领域的应用做参考。 相似文献
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设计了一种基于吸波材料的屏蔽领结天线, 采用金属腔体提高天线的方向性, 并起到屏蔽作用.通过在腔体内部填充吸波材料, 来降低电磁波在金属腔内部的反射, 并改善天线的频率域特性和时间域信号的拖尾.通过有限元电磁仿真软件HFSS设计天线模型, 优化天线参数.实际天线的各项参数较加吸波材料和金属腔之前得到了有效改善:频率域上, 天线的中心频率有所降低, -10 dB以下带宽从原来的100 MHz提高至200 MHz; 时间域上, 脉冲信号的宽度降低, 信号拖尾得到了明显改善.实际探测证明, 在天线背部加填有吸波材料的金属屏蔽罩, 可以有效降低来自上方的干扰, 分离直达波和有用信号, 提高探测精度. 相似文献
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The influence of complex material coverings on the quality factor of simple radiating systems 总被引:1,自引:0,他引:1
Tretyakov S.A. Maslovski S.I. Sochava A.A. Simovski C.R. 《Antennas and Propagation, IEEE Transactions on》2005,53(3):965-970
The influence of material coverings on the antenna quality factor is investigated for radiators formed by thin electric or magnetic line sources. It is shown that thin uniform and symmetric layers of arbitrary passive materials (including Veselago, left-handed, or double-negative materials) cannot help to overcome the bandwidth limitations imposed by the amount of energy stored in the antenna reactive field. Alternative possibilities offered by complex composite materials in the antenna design are identified. 相似文献
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An electromagnetic bandgap resonator antenna 总被引:10,自引:0,他引:10
Cheype C. Serier C. Thevenot M. Monediere T. Reineix A. Jecko B. 《Antennas and Propagation, IEEE Transactions on》2002,50(9):1285-1290
This paper introduces a new explanation of the electromagnetic bandgap (EBG) material properties using the study of the EBG structures in the frequency domain and reciprocal space. Once the behavior of such a material is understood, the properties of the EBG are used in order to make an EBG antenna. The antenna is realized with dielectric EBG rods. Its directivity is increased compared to a simple patch antenna. Such a device allows us to obtain a high gain with a very thin structure. 相似文献
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A symmetric five-layer slab waveguide with anisotropic and dispersive left-handed material (LHM) in the core and righthanded
material (RHM) in other layers is investigated. Through Maxwell’s equations and a transfer matrix method, the dispersion equations
for the TE oscillating guided modes are obtained. Under consideration of two extremely anisotropic cases, some mode dispersion
curves are plotted. The zero-order TE oscillating guided mode exists. Meanwhile, with the increase of mode number, their dispersion
curves move to left or right, corresponding to positive or negative dielectric permittivity and magnetic permeability in the
longitudinal direction. Besides, as the core thickness increases, mode dispersion properties change and three propagation
properties appear: positive group velocity, negative group velocity and zero group velocity. The negative group velocity indicates
the characteristics of the left-handed materials, and the zero group velocity implies that electromagnetic waves are trapped
in the waveguide completely. 相似文献
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Directive photonic-bandgap antennas 总被引:15,自引:0,他引:15
This paper introduces two new photonic bandgap (PBG) material applications for antennas, in which a photonic parabolic reflector is studied. It is composed of dielectric parabolic layers associated to obtain a PBG material. The frequency gap is used to reflect and focus the electromagnetic waves. This device has been designed using a finite-difference time-domain (FDTD) code. FDTD computations have provided the theoretical reflector's directivity. These results are in good agreement with measurements, and it appears that the PBG reflector presents the same directivity as a metallic parabola. A second application uses a defect PBG material mode associated with a metallic plate to increase the directivity of a patch antenna. We explain the design of such a device and propose experimental results to validate the theoretical analysis 相似文献