【求实唯新】Metantennas (陈志宁） 27

Panda Chen

二零二二年十一月十二日

在天线设计中，最难的是控制方向图。因为方向图是由电流在空间的幅度，相位及极化所决定的。此文，通过reactive impedancesurface对近（不规则）地电磁场的控制，实现对远区辐射场的调控。应用场景是WLAN AP天线的全覆盖。

二零二二年六月十五日

二个学生（DR SU YUANYAN and DR XU RUOLEI） 一条龙式的探索。期待着进一步完善设计方法，早日为工程所用。

图一：用PCB实现了平面三维龙伯天线设计与加工。

图二：提出沿径向平面化的变换光学法及全模式龙伯天线设计。

图三：提出完整变换光学法模型及平面龙伯天线设计。

图四：基于完整变换光学法模型设计的零焦距龙伯天线。

1. Y. Su and Z. N. Chen, "A Flat Dual-Polarized Transformation-Optics Beamscanning Luneburg Lens Antenna Using PCB-Stacked Gradient Index Metamaterials," in IEEE Transactions on Antennas and Propagation, vol. 66, no. 10, pp. 5088-5097, Oct. 2018, doi: 10.1109/TAP.2018.2858209.

2. Y. Su and Z. N. Chen, "A Radial Transformation-Optics Mapping for Flat Ultra-Wide-Angle Dual-Polarized Stacked GRIN MTM Luneburg Lens Antenna," in IEEE Transactions on Antennas and Propagation, vol. 67, no. 5, pp. 2961-2970, May 2019, doi: 10.1109/TAP.2019.2900346.

3. R. Xu and Z. N. Chen, "A Transformation-Optics-Based Flat Metamaterial Luneburg Lens Antenna With Zero Focal Length," in IEEE Transactions on Antennas and Propagation, vol. 70, no. 5, pp. 3287-3296, May 2022, doi: 10.1109/TAP.2021.3137528.

4.R. Xu and Z. N. Chen, "A Hemispherical Wide-Angle Beamsteering Near-Surface Focal-Plane Metamaterial Luneburg Lens Antenna Using Transformation-Optics," in IEEE Transactions on Antennas and Propagation, vol. 70, no. 6, pp. 4224-4233, June 2022, doi: 10.1109/TAP.2021.3138554.

二零二二年五月三日

R. Xu and Z. N. Chen, "A Hemispherical Wide-Angle Beamsteering Near-Surface Focal-Plane Metamaterial Luneburg Lens Antenna Using Transformation-Optics," in IEEE Transactions on Antennas and Propagation, June 2022

前一篇工作关于光学变换在Luneberg lens设计中正确应用的理论讨论（姊妹篇）。这是一个设计的验证，即，在对经典圆球Luneberg lens进行平面变换时将透镜的焦点保持在被压缩的平面上的设计。在这之前的设计都无法做到这点。而这点在天线设计中是非常重要的。否则，焦点远离天线的总体积并没有被明显压缩，透镜自身的反射很大，以及透镜的扫描角度被大大的压缩了。

二零二二年四月三十日

R. Xu and Z. N. Chen, "A Transformation-Optics-Based Flat Metamaterial Luneburg Lens Antenna with Zero Focal Length," in IEEE Transactions on Antennas and Propagation, doi: 10.1109/TAP.2021.3137528.

图片是用来验证平面化的二维luneberg透镜。

这个工作从变换光学在luneberg透镜平面化设计中的应用出发，研究了如何正确应用TO的方法。第一次成功地将馈源保持在TO变换后的luneberg透镜表面上。

Abstract:The transformation-optics (TO) technique has been widely applied in the volume reduction of Luneburg lens (LL) in both optical and microwave regimes. However, it is found that the focus is usually not located on the surface of the transformed LL anymore after applying TO. The focus location shift results in a limited volume reduction, severe reflection from the new lens surface, and limited scanning range with increased spillover loss. This paper theoretically studies and proposes a TO-based LL antenna with zero focal length by considering the phase mismatch caused by the space discontinuity. The study first reveals that the transformation of an LL alone without sustaining the original boundary inherently deteriorates the original focusing property even before exerting any approximation. To validate the idea, a flat metamaterial LL antenna using TO is proposed, approximated, and fabricated using an integrated dielectric and conductive three-dimensional printing manufacturing process. The feeding patch antenna remains on the surface of the transformed lens. The thickness of the proposed antenna is reduced to 1/3 of a traditional LL in its boresight, while a ±20° beam scanning range is achieved with linearly shifted feedings. The study verifies that it is essential to ensure phase matching at the radiation boundary to maintain the original focusing property of an LL. The information derived from the study evidences the conditions of the enforcement of the TO in electromagnetic problems such as dielectric lenses.

二零二二年四月三十日

R. Xu and Z. N. Chen, "A Compact Beamsteering Metasurface Lens Array Antenna With Low-Cost Phased Array," in IEEE Transactions on Antennas and Propagation, vol. 69, no. 4, pp. 1992-2002, April 2021, doi: 10.1109/TAP.2020.3026905.

phased array具有强大的波束形成和扫描功能，是个非常棒的天线技术。现在已经成为高端天线系统中的标配。然而，phased array的天线馈电网络与相移的复杂性使得系统的成本与功耗一直都是非常挑战的。该文利用metalens array来减少phase shifter的数量和以及透镜带来的天线厚度。从天线架构和metalens的应用上有所突破。抛砖引玉，期待业界能够在系统样机方面有所推进。

该工作已经几次获学生论文竞赛奖，并应邀在三大社交媒体上分享。根据Xplore （IEEE TAP），迄今为止，已有3098次 full text views。

Abstract: A metasurface (MTS) lens array (MLA) fed by a phased array with less phase shifters (PSs) is proposed for compact low-cost beamsteering applications. By dividing a single-large-aperture lens into N small-aperture lens elements with the focus-to-diameter ratio of a lens antenna unchanged, the overall thickness of the proposed antenna is reduced by N times. The beamsteering is achieved in two steps. First, the main beam direction of MLA antenna is switched over a large angular step by shifting the feeding antennas beneath each lens element. Then, the switched beams are fine steered by a low-cost N-element phased array. Theoretical analysis using array theory is performed to work out a general design method with discussion on the taper and spillover effect of feed-power pattern on the lens array. Based on the proposed method, a three-lens linear MLA fed by a phased array is designed to operate at 10 GHz. The proposed antenna achieves a 3 dB beamwidth coverage range of ±30° with a beam crossing level higher than -3 dB and a gain tolerance of 1.6 dB with a maximum gain of 19.1 dBi. The presented antenna can be used to achieve volumetric beamsteering performance directly. The proposed design features the merits of higher gain, lower cost, simpler feeding network, less PSs, and lower profile compared with conventional full phased arrays and single-aperture lens antennas.

二零二二年四月十九日

DL-Enabled metasurface. 艺术创作的新时代。😄😊

这是一个利用先验知识基于深度学习建立起的超表面综合方法。metalens是用来展现这个方法功效的。

工作已经清楚地显示，通过深度学习综合的三层metacells，具有了前所未有的设计自由度（degrees offreedom），为突破现有技术的中的相移提供了空间。进一步，由于这个增大的设计自由度，极大地丰富了metacell set，为提高metalens的带宽与增益提供了更大的可能性。

更为重要的是，通过这个工作，我们对如何利用深度学习，这个复杂的综合过程，建立起新的综合方法有了切身体会。特别是如何target setting，即需要坚实的专业知识和具体设计方向的洞察力，有了深刻认识。

更加深入的思考是如何理解，人与机器，人与人工智能化机器的哲学关系；工程技术人员如何在未来强大的智能化机器社会中生存；以及未来工程研究与应用发展的必然趋势等。这些似乎更加一般性的问题，确实是个值得尽早思考的问题。

根据我有限的经验和知识，我预感，深度学习在工程，比如在天线设计上，不仅仅是优化，不是一个选项，而是一个必须。而这种发展，呼唤着也依赖着行业大师（domain master）的投入。

我正在拭目以待一个天线设计新纪元的到来。

Latest updated on 6 Aperil 2022

上一次update是二年前。二年来，我们的metantenna研究已经有了许多新的有趣的工作。特别是对What's next有了一些想法。

我以为，Metasurfaces在天线技术研究中有三个重要工作（请见我们最近在EUCAP2022上的分享）：

一，MTS自身的理论及功能研究;

二，新的模型，优化和综合方法的研究与应用;以及

三，提高现有技术的性能上限及增加新的功能。

过去几年，充分利用现有的有限资源，我们一直都在这三个主方向上攻城，但是不掠地。

新应用：phased arrays

新方法新应用：Characteristic Mode Analysis

新方法新边界：Deep Learning

Metantennas

what is an antenna?

A: A piece of simple metal but highly complex tasks.

A: An artswork!

A: A magic!

As promised, I will selectively introduce part of our antenna work based on magic metamatetials. Before reading this introduction, suppose you have known the concept of metamatetials very well and agreed with my understanding of metamaterials with three key features from enclosed link. Otherwise, we don't have common sense to discuss the issues here.

http://a.meipian.me/1kugkm8?from=groupmessage&isappinstalled=1

遵守承诺，我会逐步介绍目前我们基于电磁泛材料所发展的天线技术。不过在此之前，希望你已经十分了解电磁泛材料的概念，并认可我对电磁泛材料三大要素的理解。否则，我们就失去了讨论问题基点，鸡同鴨讲了。


http://a.meipian.me/1kugkm8?from=groupmessage&isappinstalled=1


这里的想法基本上在工业界落地了。十分感谢业界对我的信任，在我们互相完全不认识的情形下，冒险投资我的团队。同舟共济，共达彼岸，开创泛材料落地市场的局面。现在泛材料的概念已经渗入到我们日常的新天线技术开发与设计中。正在艰苦前行。

一点注释：
自metamaterials被提起的第一天起，因为它打破了所有现有电磁场中物理概念的藩篱，非常自然地引起了许多争论。这种争论既是正常的，更是有益的。它大大地促进了该理论的发展与完善。

另一方面，在工程界也有很大的争议，而且这种争议并没有随着越来越多的应用的出现而减弱。原因不外乎，一是对概念，其实更多的是对表述上的不认可。二是还是缺乏的工程上成功的范例。三是没有分清科学和工程语言上的微妙区别。四是把物理概念等同于工程技术。五是没有机会真正搞明白那个概念，而是靠想像或所谓的直觉去理解。六是因为圈里的一些不实或泛美之词甚至一些学术界的江湖骗子的不齿所为。

我以为，作为工程技术研究人员的我们，最重要的是要努力明白科学语言和物理概念，然后努力把对物理概念的抽象的理论描述的科学语言转换成可设计的工程技术参数，从而架起应用与理论的桥梁。

另外，在讲述和推销这个概念时一定要客观，要分清你在和谁说话。在“忽悠”研究基金时，你可以也应该画一张梦幻之图，编一些新名词和时髦的术语，让大家憧憬。作为科学研究，就是去探索未知，就是要展开想像的翅膀。但当你谈论工程技术时，还是老老实实地把工程上的可行性放在前台，忘掉那些美妙的名词，扎扎实实地解决问题，来不得半点虚假。

搞工程技术的我，从来不参与所谓概念上的争论，那是搞物理人的事。我曾经经历过对MEI方法的争论，现在的META。对我而言，解决具体问题就是硬道理。一旦将概念成功地转化为技术，而技术又被市场采用了，就是真正的成功。至于，新技术被冠以了META还是TAME重要吗？

众所周知，物理概念是工程技术的基础。任何一个新的物理概念都有可能会对技术发展产生革命性的影响。技术要创新，就必须密切关注物理概念的变化与发展。

Since 1999, metamaterials have been scientifically researched widely. Many excellent scientific findings have covered all spectra. Potential applications have also invovled almost all EM and even physical waves or fields.

I think, the most successful applications of metamaterials have included at least absorbers and antenna radomes in EM fields before 2014. However, we have hardly seen the real industry applications of metamaterial-based antennas although many claims have been in press release. After deeply thinking, I realized that we must find a new way to avoid the two inherent drawbacks of strongly resonant double negative structures for antennas with simple structure, high efficient, and wide enough bandwidth which achieved greatly enhanced performance of interest.

*More details can be found at

http://www.e-fermat.org (《上海大学学报》) at

http://www.journal.shu.edu.cn/CN/article/showArticleBySubjectScheme.do?code=TN%20011 or http://www.cjors.cn/CN/article/showBrowseTopList.do?year=3（电波科学学报2018 Vol.33(3):239-255）.

After deeply thinking, I realized that we must find a new way to avoid the two inherent drawbacks of strongly resonant double negative structures for antennas with simple structure, high efficient, and wide enough bandwidth which achieved greatly enhanced performance of interest.

First, let us address the top general challenges of antenna engineering again as follows:

1 wide enough operating bandwidth in terms of not only impedance matching but also all performances of interest.

2 high enough gain, not only directivity but also radiation efficiency

3 simple enough structure or/and low enough cost for ease massive production.

It should be noted that the most challenging issue is that all antenna designs must meet all specifications simultaneously besides the three challenges montioned above, such as beamwidth, mutual coupling, front-to-back ratio, volume, and so on.

In 2010, we officially started our R&D&C of metamaterial-based antennas . Here, I demonstrated some of them to show how we worked out the ideas to apply the physical concepts of metamaterials in developing innovative antenna technologies for commercial applications one by one.

From more and more success stories, you may have realized that
A. the physical concepts of metamaterials have opened a new s for not only the academic research in EM fields but also, more importantly, innovative antenna design, and
B. with the metamaterial-based technologies, the limits of existing technologies, not physical limits, have been broken.

Notes on Metamaterials (MTM) vs Metasurfaces (MTS)

Conventionally, metasurface is regatded as a two-dimensional version of metamateroal. In genetal. it seems logical if we define all artificial strictures featuring unique electromagnetic properties which have yet found in nature as metamaterials. But the comparison of both shows us the difference between them if we consider metamaterials as three-dimensional uniform/periodic structures.

At least two important aspects differentiate them besides the dimension of structures. The one is that the MTM is usually a structure of periodic arrays of elements in three dimensional way which while the MTS is formed with non-uniform arrayed unit cells on a sutface. Certainly, the MTS can be considered as a cross-section of a non-periodic MTM.

TECH21 Metaline based Loop s

metaline based loop antenna:一种基于engineered dispersion line的环天线。通过在单线上的分布式加载，改变单线色散特性的控制，实现不改变频率的大波长工作状态。利用这个特性，可以保证在电大尺寸闭环天线上电流（驻波）不反转。利用这个特性，可以用来设计电大尺寸的近场磁耦合天线和远场全向辐射天线。

Metamaterial is a historic physical concept stemmed from microwave lens antenna design about 80 years ago. in the past two decades, it has been developed significantly. It is very interesting to see how optical researchers developed the concepts with huge number of publications and finally microwave researhers translated the concepts to technology for production in market again. Our team have worked on the translational research on metamaterial-based antenna design--metantennas and successfully applied many of them in products closely working with industry partners. I think this is a right direction of EM metamaterial R&D in future. I I posted the publication list of our papers about metaline based loop antennas. Some of these ideas have been real industry designs and licensed to industry partners for RFID and WLAN antennas. all comments are most welcome.

Tech20 IEEE TAP:  Metantennas

Special Issue of IEEE TAP (March 2020) is about Metamaterials and Metasurfaces. Seven papers coauthored by me have been published. This is another record Special Issue of IEEE TAP (October 2009) about millimeter-wave antennas in which we published five papers.

This year has been the twentyth year since the concept of new metamaterials was proposed. The investigation of metamaterials has been widely evolved from the double-negative materials to the generalized EM structures having unique EM properties. A large number of excellent theoretical fundings have been published. Fortunately, the research has gone on the way towards applications. In particular, metamaterial-based metantennas have finally been commercialized and applied in more and more engineering systems.

Our team has been ed on R&D&C of metantennas for more than a decade. 风斯在下，the collaboration with industry has brought in many challenges for our research while our metantenna technology has greatly enhanced the competition of antenna technology in market.

TECH19 Flat Meta Luneburg

To bridge the gap between the physical concepts and engineering technology of metamaterials

对波在传输系统中的传播，如果用折射率来描述是从材料角度解释。如果用色散特性来描述则更加直接。我们在分析零相移线时，用的是后者。

一直以来，都有对超构的工程与物理的不同解释角度。因为用了折射率，才有了material的说法。而工程上，用等效的材料特性是无法进行直接的工程设计，还是更依赖散射参数或色散特性，也是落地metamaterials的方法。后者更具工程设计意义，而从材料角度解释则更具一般性，就是本构关系。

#250 用17层pcb板实现天线

#263 TO是沿着径向方向，扫描角度更宽

Technology 18（集锦）

IEEE TAP 二月刊出版了。我们的三篇都是metantennas。

Technology 17

Summary of Metasurface Antennas using Characterisatic Mode Analysis

List I of our relevant publications

List II of our relevant publications

TECHNOLOGY 16

Title: "Truncated Impedance-Sheet Model for Low-Profile Broadband Nonresonant-cell Metasurface Antennas using Characteristic Mode Analysis”

Abstract: A unit-cell-free truncated impedance-sheet model (ISM) is proposed for the modeling and design of low-profile broadband metasurface antennas (MAs) composed of non-resonant unit cells using characteristic mode analysis (CMA). Different with conventional MAs with locally resonant unit cells, the non-resonant unit cells of the proposed MAs only contribute to the grid impedance and the MA operates with the global resonances of the metasurfaces. New measures are also reported to incorporate a higher-order metasurface mode for wideband radiation. A low-profile broadband MA is designed at the 5-GHz WiFi bands for proof of concept. Three modes are excited simultaneously, including a quasi-TM01 mode, a quasi-TM21mode, and a dipole mode. With a size of 0.8λL × 0.8λL × 0.087λL (λL is the wavelength in free space at the lowest operating frequency), the prototyped MA achieves a bandwidth of 45% with |S11| < ‒10 dB, boresight gain of 8.5~11.6 dBi, and 3-dB beamwidth of 40˚~60˚/43˚~65˚ for the E-/H-planes. 

Published in: IEEE Transactions on Antennas and Propagation

Volume: 66, Issue: 10, Oct. 2018, Page(s): 5043 – 5051.

Significances: For the first time, the characteristic mode of a frequency-dispersive impedance sheet is analyzed. New methods proposed for manipulating multiple resonant modes of metasurfaces by non-resonant unit cells led to low-profile multi-mode wideband metasurface antennas.

TECHNOLOGY 15

Title: “Metasurface-Based Shared-Aperture 5G S-/K-Band Antenna Using Characteristic mode analysis.”

Abstract:

An S/K-band metasurface-based antenna with a shared aperture is proposed for 5G applications. The metasurface is designed with the dual-band characteristics for two antennas to work in the same aperture without interference. Based on the characteristic mode analysis (CMA), 3×3 metasurfaces are proposed for the S-band radiation. To radiate the K-band electromagnetic wave without blocking, the metasurfaces are discretized by the sub-cell of a square ring and an inner square patch to achieve a frequency selective function. Then, as an example, the microstrip-fed slot is used to drive the metasurfaces at the S-band while an 8×8 substrate integrated waveguide (SIW) slot array antenna between microstrip and metasurface is designed at the K-band. The measurement shows the 10-dB return loss bandwidths of 23.45% and 4.8% and the realized gain of 7.52-10.88 dBi and 21.3-22.4 dBi over the S-band (3.2-4.05 GHz) and the K-band (25.22-26.46 GHz), respectively.

Published in: IEEE Transactions on Antennas and Propagation (accepted in September 2018)

Significance: Shared aperture antenna for dual-band operation using metasurface and Characteristic Mode Analysis

TECHNOLOGY 14

Title: A Dual-Band Metasurface Antenna Using Characteristic Mode Analysis

Abstract:

A compact metasurface based antenna is proposed for dual-band operations. The proposed metasurface is designed on a single-layered substrate including an array of modified 3×3 squared patches. Each of four corner patches is split into four fractional patches while the four edge patches are evolved into Malta crosses and the center patch is scaled. A substrate integrated waveguide (SIW) based Y-junction cavity-fed dualslot drives the metasurface with multiple impedance resonances. Based on the predicted modal behaviors of metasurface using a characteristic mode analysis (CMA), as an example, an antenna operating at three resonant modes at 28 GHz, 33 GHz, and 36 GHz, respectively is designed for the dual-band operation for the coming 5G. The proposed design shows that the measured impedance bandwidths (return loss larger than 10 dB) are 23.7– 29.2 GHz and 36.7–41.1 GHz with the achieved gain of 4.8–7.2 dBi and 8.9–10.9 dBi, respectively. The proposed dual-band antenna features the advantages of low-profile and wideband, suitable for the coming dual-band 5G applications.

Published in: IEEE Transactions on Antennas and Propagation (Early Access/Oct 2018 Issue)

Significance: Shared aperture antenna for dual-band operation using metasurface and Characteristic Mode Analysis

二零一八年八月十四日

感谢褚庆昕兄教授的邀请，为《电波科学学报》撰稿一篇。匆忙成文，诚请指教!

摘要 惠更斯电磁超构表面脱胎于现代三维超构材料,是一种特殊的二维亚波长阵列结构. 基于经典电磁学惠更斯等效原理,惠更斯电磁超构表面可以灵活地调控电磁波的传播和电磁场的分布,其独特的电磁特性给天线的创新带来了巨大的机遇. 文章将综述惠更斯电磁超构表面在微波天线中的研究进展,简要介绍惠更斯超表面的基本概念和原理并总结其在微波天线设计中的应用,重点阐述三种惠更斯超构表面天线技术及其设计案例. 最后,展望惠更斯超构表面在天线工程中的广阔应用前景.

关键词 ： 电磁超构表面, 超构材料, 惠更斯原理, 色散特性分析, 特征模分析, 微波超构表面天线, 低剖面宽带天线, 超构表面透镜天线, 多波束天线, 波束控制, 天线去耦合

Abstract：Based on classic electromagnetic Huygens’ Principle and the concept of modern metamaterials, metamaterial Huygens surface, namely, metasurface (MTS) is presented to be the two-dimensional analogues of metamaterials. With the dense arrays of electrically small unit cells, the MTS can control electromagnetic-waves and fields in either usual or unusual ways. Such unique electromagnetic properties greatly offer additional opportunities to innovate new antennas. This paper updates the latest progress in the MTS based antenna at microwave bands. First, the concept of the MTS is briefly introduced with a summary of applications of the MTS in microwave antenna design. After that, three of selected MTS based antenna techniques are elaborated with design examples. Finally, the promising applications of the MTS in antenna engineering are commented.

Key words： metasurface metamaterial Huygens’ Principle dispersion analysis characteristic mode analysis microwave metasurface antenna low-profile broadband antenna metasurface lens antenna multibeam antenna beam steering antenna decoupling

收稿日期: 2018-05-07

通讯作者: 陈志宁 E-mail: [e-mail]

引用本文:

陈志宁，刘炜，李腾，林丰涵，江梅. 惠更斯电磁超构表面微波天线的研究进展[J]. 电波科学学报, 2018, 33(3): 239-255.

CHEN Zhi Ning，LIU Wei，LI Teng，LIN Feng Han，JIANG Mei. Progress in microwave Huygens’ metasurface antennas. Chinese Journal Of Radio Science, 2018, 33(3): 239-255.

链接本文:

http://www.cjors.cn/CN/10.13443／j.cjors.2018050701 或 http://www.cjors.cn/CN/Y2018/V33/I3/239

年年年相同，岁岁岁相异。

无奈时光去，只有快乐留。
痴情麦它谜，戏游天线艺
拥抱戌狗旺，不记酉雞鸣。

祝大家新年快乐,万事如意!给大家拜年!

在过去的二零一七年，我们在metamaterial特别是metasurface antenna的机理研究，工程设计与工业设计方面有重大进展，我甚是欣慰。我会逐步地更新，与大家分享。

祝大家在新的一年里继续努力创新:

good good study,

meta meta antenna!!!

TECHNOLOGY 13

Abstract:
A method is proposed to suppress the unwanted higher-order modes (HOMs) of the metasurfaces in multiport antenna systems for improving the radiation performances using characteristic mode analysis (CMA). The proposed method is to control the modal currents under consideration by loading the unit cells of the metasurface with slots and vias. The positions of loads are determined with the aid of CMA of the metasurface. For proof of concept, the proposed technique is applied to a compact wideband four metasurface antenna system operating at 5-GHz Wi-Fi bands. With the suppression of HOMs, the split and tilted radiation patterns of the metasurface antennas are significantly improved. The concept is experimentally validated for potential compact multiport antenna applications.

TECHNOLOGY 12

A Single-layered Spoof-plasmon-mode Leaky Wave Antenna with Consistent Gain

Abstract— A single-layered leaky wave antenna (SL-LWA) exploiting the groundless spoof plasmons (SPs) structure is presented and validated to achieve consistent scanning beam and broadside gain across a wide bandwidth. The antenna is composed of single-layered meander SP cells and co-planar waveguide (CPW) to SP structure converters. The periodically arranged SP cells of the SL-LWA generate a radiating space harmonic with forward, backward, and broadside radiation against frequency change. The study and experimental validation show that the proposed SL-LWA provides the consistent gain variation less than 2.5 dB of scanning beams within the 10-dB reflection bandwidth of 10.4-24.5 GHz (or 80%). In addition, the proposed antenna offers the wideband broadside radiation with 1-dB gain variation within the frequency range of 16.5-17.2 GHz (or 4.2%). The method to design the antenna operating at desired frequencies is provided. Benefiting from the low-profile compactness and unprecedented performance, the proposed SL-LWA has promising potentials for applications in wireless systems.

Impact of the work:

Leaky wave antennas (LWAs) with their frequency sweeping beams have found wide applications in frequency scanning radars for simultaneous detection of objects located at various angles.

Conventional LWAs are suffering from three drawbacks:

a) low radiating wave generation: LWAs require to be considerably long for a satisfactory radiation.

b) complex structures: many LWAs are composed of several layers and via holes.

c) gain variation: the gain of LWAs degrades significantly at higher frequencies

Spoof surface plasmon (SSP) modes are confined surface waves with simple and single layer supporting structures, and easily can be converted to guiding waves.

A new method is proposed to generate travelling waves from SSP modes with high conversion performance using a single-layered leaky wave antenna (SL-LWA) free from ground plane and via holes with a straight-forward design procedure.

TECHNOLOGY 11

Design of a Near-Field Nonperiodic Zero Phase Shift-Line Loop Antenna With a Full Dispersion Characterization（Published in: IEEE Transactions on Antennas and Propagation ( Volume: 65, Issue: 5, May 2017 )

Page(s): 2666 - 2670)

by Yunjia Zeng, Student Member, IEEE, Zhi Ning Chen, Fellow, IEEE, Xianming Qing, Senior Member, IEEE, and Jian-Ming Jin, Fellow, IEEE

Abstract:

The tradeoff between the magnetic field distribution, the magnetic field intensity, and the interrogation zone size is one of the most challenging issues in designing a zero phase shift-line (ZPSL) loop antenna for near-field ultrahigh-frequency radio frequency identification (RFID) applications. In this communication, the dispersion characteristics, including phase and attenuation constants, of the ZPSL in a loop configuration are thoroughly analyzed, such that the important design tradeoff can be fully quantified. Based on the dispersion characteristics, a nonperiodic ZPSL loop antenna with nonuniformly arranged unit cells is proposed. Compared with the periodic configurations, the proposed nonperiodic ZPSL loop antenna shows an improved magnetic field distribution with an enhanced magnetic field intensity.

Importance:

This work is the good example how to design and optimization of a near-field loop anteena using dispersion characteristics. This work is based on the modeling we developed in Technology 6.

TECHNOLOGY 10

An Artificial Magnetic Conductor Backed Electrically Large Zero-Phase-Shift Line Grid-Loop Near-Field Antenna（Published in: IEEE Transactions on Antennas and Propagation ( Volume: 65, Issue: 4, April 2017 )

Page(s): 1599 - 1606)

by Yunjia Zeng, Student Member, IEEE, Zhi Ning Chen, Fellow, IEEE, Xianming Qing, Senior Member, IEEE, and Jian-Ming Jin, Fellow, IEEE

Abstract:

A zero-phase-shift line (ZPSL) grid-loop antenna backed by an artificial magnetic conductor (AMC) is proposed to realize a uniform and strong magnetic field distribution over an electrically large interrogation zone for near-field wireless systems. The grid-loop configuration is able to achieve a uniform magnetic field distribution over an enlarged interrogation zone by enhancing the magnetic field in the central portion of the ZPSL loop. Moreover, an AMC comprised of four-arm spiral unit cells is designed to back the ZPSL grid-loop antenna for a directional field distribution and enhanced magnetic field intensity. The proposed antenna is exemplified as a reader antenna for ultrahigh frequency near-field radio frequency identification systems. By using an Impinj Speedway reader with an output power of 30 dBm, a 100% detection rate of Impinj J41 tags is achieved up to 90 mm over an interrogation zone of 200 × 200 mm2.

Importance:

This work is the success story of metamaterial-based antenna. The metamaterial structure features wideband and low loss even for magnetic fields.

TECHNOLOGY 9

IEEE Transactions on Antennas and Propagation Volume: 65 Issue: 3 Page(s): 1141 - 1150， April 2017

（http://ieeexplore.ieee.org/document/7805179/）

'Characteristic Mode Analysis and Metasurface- Based Suppression of Higher Order Modes of a 2×2 Closely Spaced Phased Array' by Ashraf Adam Salih ; Zhi Ning Chen ; Koen Mouthaan

Abstract:

This paper studies the design tradeoffs and modal excitation of closely spaced finite-sized ground plane backed phased arrays in the work of characteristic mode theory, and proposes a method to suppress the higher order modes using a metasurface. The characteristic mode analysis also reveals the dominant modes and the excited modes for wideband operation. From the generalized method of moments impedance matrix and N-port network impedance matrix, key parameters are derived for the analysis, such as modal currents, modal radiation patterns, modal significance, modal weighting, modal radiated power, and modal near fields. The analysis includes the broadside and beamsteering radiation of closely spaced bowtie array antennas. The simulated and measured results show that it is essential for the beamsteering to have multiple modes excited simultaneously. By suppressing the higher order modes using the metasurface, the aperture efficiency and the realized gain can be improved for beamsteering cases. This analysis can be extended to a larger array and used to identify array impedance bandwidth performance in scan cases.

Importance:

This work first applied CMA in a phased array design and first used metasurface to suppress the higher-order mode in phased array design.

TECHNOLOGY 8

Abstract:

A metasurface (MTS) antenna is proposed for low-profile and wideband operation based on characteristic mode analysis (CMA). An MTS radiator formed by a diamond-slotted patch is fed by a microstrip line at its bottom through a slot centered on a ground plane. The CMA is used for the modeling, analysis, and optimization of the proposed antenna in order to reveal the underlying modal behaviors of the MTS and to guide the mode excitation. It is found that an extraordinary quisi-TM30 MTS mode and a slot mode both with wideband broadside radiation are formulated and well excited simultaneously, leading to a broadband operation. Empirical equations are outlined for speeding up design. To verify the concept, a 2×2 array with the overall size of 1.78λ0×1.78λ0×0.07λ0 ( λ0 is the free-space wavelength at 5.5 GHz) is designed and prototyped at 5-GHz Wi-Fi bands. The achieved impedance bandwidth for 10-dB return loss is 31% with the gain of 13–14.5 dBi over the operating bandwidth.

Importance:

This work first applied CMA in a metasurface antenna design. This has shown that with aid of CMA, antennas can be designed with optimized performance very quickly.

TECHNOLOGY 7

Metamaterial-based Thin Planar Lens Antenna for Spatial Beamforming and Multibeam Massive MIMO

by Mei Jiang et al

Published in IEEE Transactions on Antennas and Propagation. Vol.65, No.2, pp.464-472, Feb 2017

Abstract:

A metamaterial-based thin planar lens antenna is proposed for spatial beamforming and multibeam massive multiple- multiple-output (MIMO) systems. The antenna consists of a planar lens and a linear array of receive/transmit elements. To lower the insertion and reflection loss, the lens is formed by the two-layered ultra-thin metamaterial-based surface separated with air and fed by substrate integrated waveguide (SIW)-fed stacked-patch antennas. The effects of the focal-to- diameter (f/D) on the power distribution of the lens are investigated to work out a design method. A planar lens antenna fed with seven elements is, for example, designed to operate at 28-GHz bands. The measured results show that the proposed antenna can achieve a scanning coverage of ±27º with a gain tolerance of 3.7 dB and a maximum gain of 24.2 dBi with an aperture efficiency of 24.5% over the operating bandwidth of 26.6-29 GHz. The lens antenna also features the advantages of compact size, low cost, lightweight, simple feeding network, and easy integration with other circuits for next generation mobile communication and radar systems.

 

Importance:

This work is the first implemrntation of a planar lens based massive MIMO antenna operating at 28 GHz bands for coming 5G applications.

TECHNOLOGY 6

Modeling and Characterization of Zero-Phase-Shift Lines (ZPSL) and Optimization of Electrically Large ZPSL Loop Antennas for Near-field Systems（Published in: IEEE Transactions on Antennas and Propagation ( Volume: 64, Issue: 11, Nov. 2016 )

Page(s): 4587 - 4594）

by Yunjia Zeng, Student Member, IEEE, Zhi Ning Chen, Fellow, IEEE, Xianming Qing, Senior Member, IEEE, and Jian-Ming Jin, Fellow, IEEE

Abstract:

A methodology for modeling and characterization of a zero-phase-shift line (ZPSL) structure is presented, and a ZPSL-based electrically large loop antenna is optimized for near-field wireless systems. The ZPSL loop is first analyzed with a full-wave driven-mode solver to obtain the dispersion curve. An equivalent circuit model is then presented for characterizing the ZPSL structure. Based on the dispersion analysis, a design guideline is proposed for the ZPSL loop antenna to enlarge its interrogation zone, where a uniform magnetic field distribution is desired. A design example at 915 MHz shows that the perimeter of the ZPSL loop antenna with a desired uniform magnetic field distribution can be optimized up to 2.5 operating wavelength, which is much larger than those reported with 2 operating wavelength, achieving a 56% increase in the area of the interrogation zone. The proposed method can be applied in the antenna design for near-field wireless systems such as wireless charging, radio-frequency identification (RFID), near-field communications (NFC), and magnetic resonance imaging (MRI).

Importance:

This work is a detailed and correct physical explanation of designs in Tech 5. Due to the single-wire structure, we can't use transmission line theory to model the structure for further study so that we don't know the upper bound of the electrical size of the loops.

With aid of dispersion analysis, we first proposed a currect and model the structure with high accurancy. With the analysis, we finally discovered the limit of the zero-phase shift loops and optimize the designs based on the new findings.

TECHNOLOGY 5

A: Control of near-zone magnetical field at UHF bands

IEEE Transactions on Antennas and Propagation (Volume:58 ,  Issue: 12 )
Page(s):3829-3838


A Broadband UHF Near-Field RFID Antenn

A broadband segmented loop antenna is presented for ultra high frequency (UHF) near-field radio frequency identification (RFID) applications. Using a segmented line, the current distribution along the loop is kept in phase even though the perimeter of the loop is more than two operating wavelengths so that the proposed antenna generates strong and even magnetic field distribution in the near-field zone of the antenna.

 The antenna prototype, printed onto a piece of FR4 substrate, with an overall size of , achieves a large interrogation zone of with good impedance matching and uniform magnetic field distribution over the entire UHF RFID band of 840-960 MHz.

Importance:

With the introduction of capacitance into the thin - wire loop, the phase constant is reduced so that the phase along the wire hardly varied, that is, the electric current along the loop wire will propagate in the same direction even when the circumference of the loop wire is longer than jalf wavelength in free space. This type of current distribution will generate 1 uniform near-zone magnetic field in the loop area and 2 consistent far-zone radiation in planes where the loop is oriented in parallel.

After this paper, there have been many designs for UHF near-field RFID reader antennas, omnidirectional horizontally polarized radiation for WiFi and so on. We have reached 500×500mm consistent magnetical field coverage using single loop antenna.

B. Generation of Omni-directional Radiation with Horizontal Polarization

 An Omnidirectional Circularly Polarized Antenna Array


IEEE Transactions on Antennas and Propagation, Volume:64 Issue:2, pp. 574-581, 2016

An omnidirectional circularly polarized (CP) antenna array is proposed. The antenna array is composed of four identical CP antenna elements and one parallel strip-line feeding network. Each of CP antenna elements comprises a dipole and a zero-phase-shift (ZPS) line loop. The in-phase fed dipole and the ZPS line loop generate vertically and horizontally polarized omnidirectional radiation, respectively. Furthermore, the vertically polarized dipole is positioned in the center of the horizontally polarized ZPS line loop. The size of the loop is designed such that a 90° phase difference is realized between the two orthogonal components because of the spatial difference and, therefore, generates CP omnidirectional radiation.

A 1 × 4 antenna array at 900 MHz is prototyped and targeted to ultra-high frequency (UHF) radio frequency identification (RFID) applications. The measurement results show that the antenna array achieves a 10-dB return loss over a frequency range of 900-935 MHz and 3-dB axial-ratio (AR) from 890 to 930 MHz. At the frequency of 915 MHz, the measured maximum AR of 1.53 dB, maximum gain of 5.4 dBic, and an omnidirectionality of ±1 dB are achieved.

Importance

Similar to Tech 5A, the current along the loop is consistent in terms of phase and amplitude. Such a current distribution will generate consistent far-zone radiation horizontally where the loop is oriented in parallel to a groud plane.

With similar design, antennas were also designed at 2.4GHz bands for industry products.

The 12 more papers presented at conferences are not listed here.

TECHNOLOGY 4

 IEEE Transactions on Antennas and Propagation Volume:63 Issue:9 2015 pp.4156-4160

Broadband and Ultrathin Frequency-Dispersive Metamaterial Screen for Reflectivity Reduction

Importance:

We first proposed a frequency-dispersive magnetic material substrate for the ultra-thin broad bandwidth of metamaterial-based microwave absorber.

A frequency-dispersive magnetic material substrate is proposed to achieve the broad bandwidth of metamaterial screens for microwave absorption. Resonance-like ferrites with frequency-dispersive properties at resonant frequencies are applied as substrate. By mixing the multiple types of resonance-like ferrites, the desired bandwidth of frequency-dispersive magnetic material is further broadened.

Simulated and measured results show that the proposed metamaterial screen can operate from 7.9 to 14.6 GHz with the reflectivity of less than -10 dB with thickness of only 1.1 mm (0.029 λr,). A figure of merit (FoM) proposed to uate the absorption performance of the screen is 20.6 for the proposed screen.

TECHNOLOGY 3

The paper was published at IEEE Trans AP Vol 64 No 6 pp.1-6 June 2016.

Importance:

We first feed a dieletric resonator antenna (DRA) using Spoof Surface Plasmon (SSP)-based Transmission Lines (TLS) . Compared with conventional microstrip-fed DRA, the missed models are well excited by groundless SSP-TLS. This is also an important milestone to apply SSP concepts in antenna engineering.

　　TECHNOLOGY 2

Importance:

We first model Spoof Surface Plasmon (SSP)-based Transmission Lines (TLS) using equavlent circuits. The proposed model is a necessary step for engineers to include SSP TLs in system design sofeware packages, for instance, ADS. This is also an important milestone to apply SSP concepts in microwave engineering.

paper:

Design and Modeling of Spoof Surface Plasmon Modes-Based Microwave Slow-Wave Transmission Line

IEEE Transactions on Microwave Theory and Techniques  (Volume:63 ,  Issue: 6 ) 2015 pp. 1817 - 1825

This paper presents a theoretical model and validates experimentally the microwave slow-wave transmission line (SW-TL) based on spoof surface plasmon (SSP) modes. Equivalent circuit models are first presented for characterizing the SSP structures and developed to serve as an insightful guideline to design the SW-TL at a given cutoff frequency and Bloch impedance.

A mode converter connecting a conventional microstrip transmission line to the SW-TL is necessarily proposed to ensure that the quasi-TEM modes of the microstrip line are gradually transformed to the operating TM modes of the SW-TL. The presented schematic of SW-TL paves a promising avenue for the unprecedented interconnector footprint miniaturization of integrated circuits, and the enhanced electromagnetic compatibility, for example, in multilayered monolithic microwave integrated circuits.

TECHNOLOGY 1

Importance:

First, we use the metasurface as a ultra-low profile patch-like antenna with high gain across wide bandwidth rather than AMC, HIS, EBG, Superstrate/lens or high-permittivity loading.

paper 1

Metamaterial-Based Low-Profile Broadband Mushroom Antenna

 IEEE Transactions on Antennas and Propagation Volume:62 Issue:3 2014

A metamaterial-based broadband low-profile mushroom antenna is presented. The proposed antenna is formed using an array of mushroom cells and a ground plane, and fed by a microstrip line through a slot cut onto the ground plane. With the feeding slot right underneath the center gap between the mushroom cells, the dual resonance modes are excited simultaneously for the radiation at boresight.

<h3><font color="#010101">A transmission-line model integrated with the dispersion relation of a composite right/left-handed mushroom structure is applied to analyze the modes. The proposed dielectric-filled (εr=3.38) mushroom antenna with a low profile of 0.06λ0 ( λ0 is the operating wavelength in free space) and a ground plane of 1.10λ0×1.10λ0 attains 25% measured bandwidth with(|S11| <; - 10dB) 9.9-dBi average gain at 5-GHz band. </font></h3>

Across the bandwidth, the antenna efficiency is greater than 76%, and cross-polarization levels are less than -20 dB.

paper 2

IEEE Transactions on Antennas and Propagation Volume:62 Issue:9 2014

60-GHz Thin Broadband High-Gain LTCC Metamaterial-Mushroom Antenna Array

Using the mushroom radiators, the single-element achieves high gain comparable to a 2×2 patch array but lower losses caused by the feeding network used in an array. This is vital important for the high gain antenna design where usually the antenna arrays suffer from high losses caused by feeding power dividers. Therefore, we use the proposed mushroom antenna as an element of array to reduce the feeding losses.

A low-profile broadband metamaterial-mushroom antenna array is proposed for high-gain 60-GHz band applications. The antenna array consists of a single-layer mushroom radiating structure and a simplified single-layer substrate integrated waveguide (SIW) feeding network. A new transmission-line based model is presented to estimate the resonant frequencies of the operating TM10 and antiphase TM20 modes.

An 8 × 8 mushroom antenna array is designed and prototyped using low-temperature cofired ceramic (LTCC), the measurement shows the antenna array with the feeding transition proposed an impedance bandwidth of 56.3-65.7 GHz with a boresight gain greater than 21.2 dBi and up to 24.2 dBi at 62.3 GHz. The proposed antenna array features the merits of high gain, broadband, compact size, and low cross-polarization levels.

篇头的背景图片，不是天线工程師设计的，但是是metasurfaces。想知道其中的故事吗? 请看下面几张照片。

朋友留言

南京大学 冯一军:你们的工作推进了超材料向应用的转换[Tongue]

南京大学 陈静:
呵呵，异形同质

北京中国传媒大学 朴大志:
感觉这个第一波还没怎么开始就结束了！
只有对超材料工作机理的深入理解和对传统天线性能受限的本质原因的揭示才可能提出有重大突破的结构，you did it!

兰州大学 牛调明:
陈教授的大作，而且是专业的，必须分享！[呲牙]
陈老师的团队好强大！[呲牙]

南京发小应爱萍:
陈教授：创新高技术不要光介绍论文要感紧申请专利，否则就会变成别人的了，没看到国内磁材概念股炒翻天啦[调皮]

日本 佘元峰:
这篇论文貌似拜读引用过[白眼]

我必须要感谢我的同事和学生们卓越的技术贡献，精诚的团队协作和不懈的努力奋斗。有了他们才是我职业的最大成就。你会在陆续张贴的已发表论文中看到他们的名字，也拜托大家记住他们[抱拳]

当然，我也铭记那些一直支持帮助我们相关工作的朋友们。无法一一列出，藉此告谢!