Novel application of a new metamaterial complementary electric LC resonator for the design of miniaturized sharp band‐pass filters

In this article, we introduce a new metamaterial complementary electric LC resonator (CELC) and investigate its operational mechanism, characteristics, and potentialities for application in microwave components and devices, such as filters. We consider the excitation of CELC by the electric and magnetic fields of microstrip lines and its resonance characteristics by the diagrams of effective permittivity (ε_eff) and permeability (μ_eff). A circuit model is obtained by the consideration of its coupling with the loaded microstrip line. We then realize a novel left‐handed (LH) cell by the combination of the CELC resonator and a short circuited stub. It is designed by the least mean square method. We finally use the cascade connection of such LH cells for the design of a miniaturized narrow‐band band‐pass filter with high out of band rejection. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2013.     

“工”字型径向弹性超材料零频起始带隙特性研究

为了得到零频起始带隙,提出"工"字型径向弹性超材料,并研究了其不同约束状态下弹性波的传播特性。通过对色散关系,频响函数和本征模位移场计算研究,发现在双面约束状态下可产生0~16 849 Hz的零频起始宽频带隙,主要由约束作用引起的模态转变产生。进一步,通过研究有限周期结构的方向振动位移场,发现零频起始带隙产生的机制为局域共振机制。最后,分析了结构参数对零频带隙位置及带宽的影响。研究结论可以应用于超低频减振等工程领域。     

宽带吸波超材料的研究进展

宽带吸波材料在隐身、电磁屏蔽和兼容等领域具有重要应用价值。受制于材料的电磁频散,传统吸波材料的低频吸收性能难以进一步提升。近年来发展的吸波超材料由于具有不同于传统材料的吸波原理而广受关注。简要概述了吸波超材料的性能、结构及特点,重点介绍了吸波超材料的新型吸收机制及宽带吸波超材料的最新研究成果,最后对其今后的发展方向做了展望。     

Influence of the geometry of a gammadion stereo-structure chiral metamaterial on optical properties

In this paper, a gammadion stereo-structure (GSS) chiral metamaterial (CMM) is described and numerically analysed at optical frequencies. The influence of the geometry of the proposed CMM on the optical properties was studied systematically. The numerical simulations exhibit that the giant circular dichroism (CD) effect, optical activity and negative refraction can be obtained by properly selecting the geometric parameters, respectively. Given the pronounced optical effects and the negative refraction property of stereo-structure CMM, many applications in ultra-compact polarization components, integrated photonics, plasmonic-enhanced sensing of biochemical substances and CD spectroscopic analysis can be envisioned easily.     

平面超材料对曲折线慢波结构行波管效率改善和杂模抑制的影响

针对U型曲折线慢波结构带状注行波管杂模抑制和互作用效率提高等面临的挑战,提出了一种开口菱形超材料结构。在综合考虑电路单元谐振性能、与U型曲折线慢波结构之间的协调配合以及电路实现可行性和结构简单等因素,通过电路设计和数值模拟优化等具体措施相结合,探讨这种超材料对增强注波互作用表面电场和抑制电路振荡的效果。在Ka波段优化的结果表明,这种超材料在抑制杂波和改善注波互作用效率方面效果明显,对此类行波管稳定性提高具有重要意义。     

基于复合左右手结构的新型超宽带巴伦

基于复合左右手(CRLH)结构的非线性相位特性,设计了一种新型的超宽带威尔金森功分器巴伦.该巴伦利用一个单元的CRLH结构代替传统微带线构成分支臂.仿真和实验结果表明该新型的巴伦具有高达120%的相对阻抗带宽、112%的相对相位差带宽、体积小、制作简单、易与MIC/MMIC技术集成等优势.     

Broadband and high-efficiency reflective polarization rotator using metamaterials

A wideband and high-efficiency 90°polarization rotator based on ultrathin planar metamaterial is presented. It consists of the metallic hexagonal patches on the top layer of the dielectric substrate and a metallic film on the bottom layer. Initially, the explanation of the physical mechanism for the polarization rotator is presented according to the anisotropy media theory. Thereafter, we have discussed the influences of the structure dimension on the performance of the proposed polarization rotator. And finally, the structure is also fabricated. Results of the test show that it exhibits over 90％ polarization conversion ratio from 841GHz to 113GHz in the condition of normal incidence.     

一种分析异向介质中导线阵列宏观效应的新方法

本文根据异向介质中细导线阵列的电磁效应,利用均匀介质与均匀传输线的等效关系,建立起电磁波在导线阵列中传播时的等效电路,以此为依据从宏观上推导出异向介质中非均匀导线阵列的有效介电常数模型,在呈现出非常清晰的物理图景的同时,为人们从宏观物理学的角度理解导线阵列的等效负介电常数效应、从实质上揭示异向介质的构成理论向前跨进了一步.数值仿真结果表明,该模型具有足够的精度.本文所得到的结论对理解异向介质的构成提供了更加清晰的描述方法,为异向介质在微波电路领域的应用提供了一套分析方法.     

非对称针尖结构对远红外超材料谐振性能的影响研究

为提高远红外超材料的品质因子Q和检测灵敏度,本文研究了一种用于金属远红外超材料的非对称针尖设计。以传统双开口方形谐振环为模型,通过理论模拟,研究了开口狭缝针尖角度变化对其电场分布、谐振频谱以及品质因子Q的影响。结果表明,非对称针尖增强了谐振环的表面电场局域性,减小了谐振峰的半峰宽,并使品质因子Q提高到传统谐振环（非针尖设计）的三倍以上。该研究结果为开发高灵敏远红外超材料传感器提供了新的思路,并为传统开口谐振环提出了一种简单实用的Q因子优化方法。     

基于超材料设计实现C/Co复合材料的超宽带吸收

本文通过简单的一步热解法合成了C/Co复合材料,在材料质量填充浓度为35%时观察到其具有优异的介电频散性能。当材料厚度2.5 mm时,该复合材料在11.2 GHz的最小反射率为-23.7 dB,小于-10 dB的带宽为3.8 GHz。为了进一步提高吸收体的吸波性能,我们利用全介质超材料的设计对吸收体的宏观结构进行优化,此方法成功地将小于-10 dB的吸收带宽扩展到15 GHz （7.0~22.0 GHz）。该研究结果可以为高性能微波吸收材料的制备工艺和结构设计提供有价值的参考。