共查询到17条相似文献,搜索用时 62 毫秒
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超材料吸波体吸波特性研究 总被引:3,自引:2,他引:1
设计了一个强谐振超材料吸波体,它由电谐环振器(Electric ring resonator)和短导线组合而成.采用数值仿真法,在8~12GHz波段提取了这种超材料的s参数,并计算了其吸渡率.单层超材料吸波体在10.2GHz处达到吸收峰,吸波率达91.3%.多层组合吸渡体在9.72GHz处峰值吸波率接近100%.与传统吸波材料不同的是,该超材料吸波体完全由金属结构组成,通过对介电常数和磁导率的灵活调节,经优化设计即可实现对入射电磁波的高吸收.另外,通过尺寸变化的多层组合结构,利用不同吸波频段的叠加效应,实现了对吸波频带的拓宽. 相似文献
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为了实现宽带平稳吸收电磁波,本工作设计了一种微波宽带完美超材料吸波体(Metamaterial absorber,MA).使用等效电路模型和COM-SOL仿真软件对其结构参数进行了优化仿真,通过电场和表面电流密度分布以及等效输入阻抗分析了MA宽带强吸收的机理,研究了其极化和斜入射特性以及各层结构的吸收响应.结果表明,电磁波正入射时MA在5~9.2 GHz的频率范围内达到了90%以上的吸收率,平均吸收率高达97.71%,特别是在5.9~8 GHz的宽带内实现了完美吸收电磁波(吸收率大于99%,反射率小于1%),并且具有良好的极化和宽入射角稳定特性.本工作提出的吸波结构整体厚度为0.12λ0,周期单元尺寸为0.29λ0×0.29λ0(λ0为吸收带中心频率的波长),通过改变中间介质层的介电常数能在保证波形基本不变的前提下调节工作频带,其具有良好的频带可移植性,能够应用于隐身技术和电磁兼容等领域. 相似文献
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设计了一种基于C型组合谐振结构的多频带超材料吸波体,通过CST微波工作室进行仿真分析,采用弓形法对超材料样品的反射率进行实验验证。仿真结果表明,该吸波体在3.28GHz、3.89GHz、6.61GHz、9.76GHz、11.43GHz实现了近完美吸收,吸收强度分别为99.67%、99.85%、98.10%、99.99%、99.25%,实测结果和仿真结果基本一致。通过表面电流分布、等效电路图以及理想阻抗匹配理论分析了该吸波体作用的物理机理。该超材料吸波体有极化无关的特性。 相似文献
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In this work, a new type of metamaterial absorber is proposed in the infrared region. This structure consists of metal-dielectric-metal. But the difference is that a square groove in the dielectric has been dug, and replaced by a metal. The simulated results show that this structure can achieve a broadband absorption. And the absorption bandwidth can be realized from 60.5 to 115.5 THz when the absorption efficiency is larger than 90%. And this structure is polarization-insensitive for incident electromagnetic waves. In addition, the structure can also achieve better absorption effect for a large incident angle, especially for TM polarized wave. What is more, a remarkably enhanced bandwidth can be realized by using a metal to fill the square groove which is dug in the dielectric. To further explain the mechanism of high absorption, the distribution of the electromagnetic field and power loss density at the resonance frequencies are analysed. And these novel properties make the absorbers have many applications including sensor, cloaking, etc. 相似文献
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Dynamic control of the absorption frequency and intensity of metamaterial absorbers has attracted considerable attention,and many kinds of tunable metamaterial absorbers have been proposed.Unfortunately,due to the integration of separate resonant unit and tunable unit,these designed metamaterial absorbers suffer from complex structure and low sensitivity.We numerically and experimentally demonstrate a tunable metamaterial absorber composed of artificial dielectric atoms as both resonant and tunable unit arrayed periodically in the background matrix on the metallic plate.Polarization insensitive and wide incident angle absorption band with simulated and experimental absorptivity of 99%and 96%at 9.65 GHz are achieved at room temperature.The absorption frequency can be gradually modulated by temperature,however,the absorption intensity at working frequency remains near unity.The dielectric atoms based tunable metamaterial absorbers with simple structure have potential applications as tempe rature sensors and frequency selective thermal emitters. 相似文献
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A planar metamaterial, consisting of double-slot cavities in a unit cell, has been investigated in detail. The results indicate that the interaction between two bright modes also leads to the transparency effect. Meanwhile, the transparency window can be adjusted by changing the length of slot cavity and the distance between two slot cavities. Finally, it is demonstrated that the planar metamaterial design may serve as a highly efficient sensor in near-infrared. The sensitivity is as high as 520 nm/RIU, and the FOM is up to 24.83. The planar metamaterial has the advantages of simple and compact structure, easy fabrication, which will greatly benefit the optical switch, nano plasmonic sensor in highly integrated optical circuits. 相似文献
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Hailong Huang Zhibo Guo Shengxiang Huang Hongjian Li Yishan Wu 《Journal of Modern Optics》2018,65(13):1521-1528
In this paper, we design a polarization-independent and broadband microwave metamaterial absorber (MMA) based on three-dimensional structure. The simulated results show that the proposed absorber has a broad absorptance band from 60.4 to 100.0 GHz with the absorptance efficiency over 90%. The effective medium theory (EMT), electric field, surface current and power loss density distributions are adopted to explain the physical mechanism of the perfect absorptance. In addition, the absorptance differences can be observed between transverse electric (TE) wave and transverse magnetic (TM) wave at oblique incidence. The proposed absorber can be utilized in many applications such as perfect absorbers and radomes. 相似文献
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利用电化学沉积自组装法制备了具有纳米银树枝结构单元的超材料吸收器。该吸收器采用"金属谐振结构单元层-绝缘层-金属层"复合结构,由直径70~140nm、非周期排列的银树枝结构单元,与聚乙烯醇绝缘层和纳米银金属层组合而成。通过改变电化学沉积过程中的条件,如沉积电压和聚乙二醇-20000浓度,可以实现对超材料吸收器吸收频率点数量和吸收强度的可控调节。实验表明这种吸收器可在538和656nm实现强度为21.1%和24.8%的多频吸收。这种超材料吸收器具有制备工艺简单,制备成本低廉,样品工作面积大等特点。 相似文献
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Young Ju Kim Ji Sub Hwang Bui Xuan Khuyen Bui Son Tung Ki Won Kim Joo Yull Rhee 《Science and Technology of Advanced Materials》2018,19(1):711-717
Flexible and ultrathin wide-band metamaterial absorbers are suggested and demonstrated in the microwave-frequency range. By using resonators of different sizes and conductive fibers on metallic-pattern layer, the total thickness of metamaterial absorber is reduced to be only 1/349 with respect to the operating wavelength at 0.97 GHz. We present the absorption mechanism in terms of the impedance matching with the free space, the distributions of surface current and the three-dimensional distributions for power loss. In simulation, the absorption was over 97% at 0.97–6.12 GHz, and the corresponding experimental absorption band over 97% was 0.87–6.11 GHz. Furthermore, the dielectric substrate of metamaterial absorbers was replaced with flexible substrate in order to have the flexibility and the broadband absorption properties. The absorption band is expanded and the high-absorption performance maintains at the same time. The total thickness of metamaterial absorber comes to be only 1/5194 of the operating wavelength at 0.75 GHz. Our work is expected to contribute to the flexible microwave/electronic devices in the near future. 相似文献
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Li Weiwei Zhao Lingyu Dai Zhaohe Jin Hao Duan Feng Liu Junchao Zeng Zhihui Zhao Jun Zhang Zhong 《Nano Research》2018,11(7):3931-3942
Nano Research - Novel thin and flexible broadband electromagnetic microwave absorbers are realized with nanocomposites and achieve a wide frequency tunability (from 10 to 17.2 GHz) by actively... 相似文献