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Accurate and broadband manipulations of harmonic amplitudes and phases to reach 256 QAM millimeter-wave wireless communications by time-domain digital coding metasurface

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National Science Review 2022年第1期9卷 36-46页

作者： Ming Zheng Chen Wankai Tang Jun Yan Dai Jun Chen Ke Lei Zhang Cheng Zhang Jin Yang lianlin li Qiang Cheng Shi Jin Tie Jun Cui Institute of Electromagnetic Space Southeast University State Key Laboratory of Terahertz and Millimeter Waves City University of Hong Kong State Key Laboratory of Advanced Optical Communication Systems and Networks Department of Electronics Peking University National Mobile Communications Research Laboratory Southeast University State Key Laboratory of Millimeter Waves Southeast University Center of Intelligent Metamaterials Pazhou Laboratory

We propose a theoretical mechanism and new coding strategy to realize extremely accurate manipulations of nonlinear electromagnetic harmonics in ultrawide frequency band based on a time-domain digital coding metasurface(TDCM).Using the proposed mechanism and coding strategy,we design and fabricate a millimeter-wave(mmWave) TDCM,which is composed of reprogrammable meta-atoms embedded with positive-intrinsic-negative *** controlling the duty ratios and time delays of the digital coding sequences loaded on a TDCM,experimental results show that both amplitudes and phases of different harmonics can be engineered at will simultaneously and precisely in broad frequency band from 22 to33 GHz,even when the coding states are imperfect,which is in good agreement with theoretical *** on the fabricated high-performance TDCM,we further propose and experimentally realize a large-capacity mmWave wireless communication system,where 256 quadrature amplitude modulation,along with other schemes,is *** new wireless communication system has a much simpler architecture than the currently used mmWave wireless systems,and hence can significantly reduce the hardware *** believe that the proposed method and system architecture can find vast application in future mmWave and terahertz-wave wireless communication and radar systems.

关键词： metasurface time-domain digital coding accurate and broadband harmonic control 256 QAM millimeter-wave wireless communications

Intelligent coding metasurface holograms by physics-assisted unsupervised generative adversarial network

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Photonics Research 2021年第4期9卷 I0079-I0087页

作者： Che liu Wen Ming Yu Qian Ma lianlin li Tie Jun Cui Institute of Electromagnetic Space Southeast UniversityNanjing 210096China State Key Laboratory of Millimeter Wave Southeast UniversityNanjing 210096China School of Electronic Engineering and Computer Sciences Peking UniversityBeijing 100871China

Intelligent coding metasurface is a kind of information-carrying metasurface that can manipulate electromagnetic waves and associate digital information simultaneously in a smart *** of its widely explored applications is to develop advanced schemes of dynamic holographic *** now,the controlling coding sequences of the metasurface are usually designed by performing iterative approaches,including the Gerchberg–Saxton(GS)algorithm and stochastic optimization algorithm,which set a large barrier on the deployment of the intelligent coding metasurface in many practical scenarios with strong demands on high efficiency and ***,we propose an efficient non-iterative algorithm for designing intelligent coding metasurface holograms in the context of unsupervised conditional generative adversarial networks(cGANs),which is referred to as physics-driven variational auto-encoder(VAE)cGAN(VAE-cGAN).Sharply different from the conventional cGAN with a harsh requirement on a large amount of manual-marked training data,the proposed VAE-cGAN behaves in a physics-driving way and thus can fundamentally remove the difficulties in the conventional ***,the physical operation mechanism between the electric-field distribution and metasurface is introduced to model the VAE decoding module of the developed *** simulation and experimental results have been provided to demonstrate the state-of-the-art reliability and high efficiency of our *** could be faithfully expected that smart holograms could be developed by deploying our VAE-cGAN on neural network chips,finding more valuable applications in communication,microscopy,and so on.

关键词： iterative remove holographic

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智能电磁感知的若干进展

雷达学报 2021年第2期10卷 183-190页

作者：李廉林崔铁军北京大学电子学系人工智能与数字经济广东省实验室东南大学毫米波国家重点实验室

智能电磁感知是电磁探测与成像的系统化和智能化延伸,是安全检查、生物医学、物联网等领域的基础性、关键性和共性问题。近年来,挖掘利用人工电磁材料和人工智能在电磁波调控与数据信息调控方面的强大能力,将其有机结合,并系统地引入电... 详细信息

智能电磁感知是电磁探测与成像的系统化和智能化延伸,是安全检查、生物医学、物联网等领域的基础性、关键性和共性问题。近年来,挖掘利用人工电磁材料和人工智能在电磁波调控与数据信息调控方面的强大能力,将其有机结合,并系统地引入电磁感知领域,发展了低成本、高性能的智能电磁感知体制,为电磁感知的进一步发展提供了关键理论和技术支撑。该文讨论了智能电磁感知的若干最新进展,为读者及时掌握该领域的最新进展提供有益帮助。

关键词：智能电磁感知人工电磁材料信息超材料人工智能机器学习深度学习

In-situ manipulation of wireless link with reinforcement-learningdriven programmable metasurface in indoor environment

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Journal of Information and Intelligence 2023年第3期1卷 217-227页

作者： Jiawen Xu Rong Zhang Jie Ma Hanting Zhao lianlin li School of Electronic Engineering and Computer Science Peking UniversityBeijing 100871China State Key Laboratory of Advanced Optical Communication Systems and Networks School of ElectronicsPeking UniversityBeijing 100871China

It is of great importance to control flexibly wireless links in the modern society,especially with the advent of the Internet of Things(IoT),fifth-generation communication(5G),and ***,we have witnessed that programmable metasurface(PM)or reconfigurable intelligent surface(RIS)has become a key enabling technology for manipulating flexibly the wireless link;however,one fundamental but challenging issue is to online design the PM's control sequence in a complicated wireless environment,such as the real-world indoor ***,we propose a reinforcement learning(RL)approach to online control of the PM and thus in-situ improve the quality of the underline wireless *** designed an inexpensive one-bit PM working at around 2.442 GHz and developed associated RL algorithms,and demonstrated experimentally that it is capable of enhancing the quality of commodity wireless link by a factor of about 10 dB and beyond in multiple scenarios,even if the wireless transmitter is in the glancing angle of the PM in the realworld indoor ***,we also prove that our RL algorithm can be extended to improve the wireless signals of receivers in dual-receiver *** faithfully expect that the presented technique could hold important potentials in future wireless communication,smart homes,and many other fields.

关键词： Programmable metasurface Reconfigurable intelligent surface Reinforcement learning Wireless link

An auto-focus algorithm for imaging of objects under a lossy earth from multi-frequency and multi-monostatic data

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Science China(Information Sciences) 2010年第9期53卷 1880-1890页

作者： liU Yanli1,2,li lianlin1 & li Fang1* 1Institute of Electronics,Chinese Academy of Sciences,Beijing 100190,China 2National Science library,Chinese Academy of Sciences,Beijing 100049,China Institute of Electronics Chinese Academy of Sciences Beijing China National Science library Chinese Academy of Sciences Beijing China

The problem of auto-focusing imaging of 2D dielectric objects imbedded in a lossy earth is *** Born approximation,the half-space spectrum Green's function is employed to formulate the half-space imaging algorithm from multi-frequency and multi-monostatic *** the fast Fourier transform can be used to achieve real-time imaging in a very short computing *** the proposed algorithm has avoided the time-consuming regularization of a large-scale ill-posed matrix,the computing time can be greatly cut *** by the principle of time reversed imaging and the minimum entropy criterion,an auto-focusing imaging algorithm is presented to remove the image degradation caused by estimated error of the unknown dielectric parameters of the *** results have shown that the proposed algorithm can provide good quality focused images for both low-contrast and high-contrast targets in a short computing time despite the inaccurate estimation of the earth electric *** proposed algorithm can be extended to three-dimensional case naturally.

关键词： multi-frequency multi-monostatic minimum entropy auto-focusing lossy earth time reversal imaging(TRI)

High-efficiency broadband polarization-independent superscatterer using conformal metasurfaces

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Photonics Research 2018年第8期6卷 782-788页

作者： HE-XIU XU SHIWEI TANG CHEN SUN lianlin li HAIWEN liU XINMI YANG FANG YUAN YUNMING SUN Air and Missile Defense College Air Force Engineering University Department of Physics Faculty of Science Ningbo University School of Electronic Engineering and Computer Sciences Peking University School of Information Engineering East China Jiaotong University School of Electronics and Information Engineering Soochow University Advanced Technique Department Key Laboratory of Aeronautics Computing Technique

Safe detection of an arbitrarily shaped platform is critical for survivability, rescue, or navigation safety in a remote region. Metasurfaces afford great potential due to their strong electromagnetic(EM) wave control. However,studies have mainly focused on the physics and design of metasurfaces on planar plates, which does not satisfy the current requirements of aerodynamics and aesthetics. Herein, we propose a sophisticated strategy to design a metasurface that can wrap over arbitrarily shaped objects with moderate curvature on which optical aberrations are commonly introduced. By designing each meta-atom on the basis of the required position and phase compensation, exact EM wavefronts are restored. For verification, several conformal metasurfaces were designed and numerically studied on metallic cylinders at the microwave spectrum. A proof-of-concept device is fabricated and is experimentally characterized. The results demonstrate the availability of the desirable dual-beam superscatterer with strong backscattering enhancement toward two directions, thus indicating that the distortions induced by an arbitrary platform can be efficiently corrected. Our method affords an efficient alternative for designing highperformance multifunctional optoelectronic devices equipped on a moderately curved platform.

关键词：安全检测电磁波通讯技术发展现状

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人工智能超材料

光学学报 2021年第8期41卷 44-60页

作者：刘彻马骞李廉林崔铁军东南大学电磁空间科学与技术研究院江苏南京210096 东南大学毫米波国家重点实验室江苏南京210096 北京大学先进光通信系统与网络国家重点实验室北京100871

人工智能的发展已经给人类社会的发展带来了极大变革,各种基于人工智能的新应用层出不穷。电磁和光学超材料对电磁波有强大的调控能力,且具有灵活的设计特性,尤其是可编程超材料的实时数字化调控能力,有利于基于人工智能技术的电磁超材... 详细信息

人工智能的发展已经给人类社会的发展带来了极大变革,各种基于人工智能的新应用层出不穷。电磁和光学超材料对电磁波有强大的调控能力,且具有灵活的设计特性,尤其是可编程超材料的实时数字化调控能力,有利于基于人工智能技术的电磁超材料的设计和智能化应用。对超材料的智能化设计、智能化结构和智能化系统进行了阐述,对于人工智能技术与电磁和光学超材料的结合,总结介绍了结构优化、架构设计和系统应用的主要进展和成果,并展望了智能超材料的未来发展方向。

关键词：光学仪器人工智能电磁超材料光学超材料信息超材料

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基于可编程超表面的Wi-Fi信号调控

雷达学报（中英文） 2021年第2期10卷 313-325页

作者：双雅李力王卓魏梦麟李廉林北京大学信息科学技术学院北京100871 北京航天测控技术有限公司北京100871

可编程超表面是由可调谐的单元在二维平面上组成的平面阵列,具有任意、动态操控电磁波波前的能力,是微波领域前沿研究方向之一。尽管目前基于可编程超表面的电磁调控研究已取得丰硕进展,但是现有技术都需要采用专用发射源主动馈电超表面... 详细信息

可编程超表面是由可调谐的单元在二维平面上组成的平面阵列,具有任意、动态操控电磁波波前的能力,是微波领域前沿研究方向之一。尽管目前基于可编程超表面的电磁调控研究已取得丰硕进展,但是现有技术都需要采用专用发射源主动馈电超表面,这不仅增加了实际系统的复杂性和成本,而且在一定程度上限制了这些技术在现实环境中的应用。因此,该文提出了一种利用可编程超表面灵活调控周围Wi-Fi信号的方法,并通过理论和实验证明了其对Wi-Fi信号的优越调控性能。首先,该文首次提出一种基于可编程超表面散射模型的高效优化算法CWGS,该算法可以重新设计可编程超表面散射场的复振幅分布,从而实现指定位置处的Wi-Fi信号显著增强。其次,该文制作了一款工作频率为2.4 GHz的大规模可编程超表面,并基于该超表面实验验证了优化算法应用于Wi-Fi信号增强调控的可行性和有效性。理论和实验结果均证明,可编程超表面可以在多个位置处实现Wi-Fi信号的动态增强。实验结果表明,经可编程超表面调控后的Wi-Fi信号强度提高了23.5 dB。该文提出的方法提高了可编程超表面在实际应用中的可用性和实用性,有望为无线通信、未来智能家居等领域开辟新的道路。

关键词：商用Wi-Fi信号可编码超表面空间能量分配

Directly wireless communication of human minds via non-invasive brain-computer-metasurface platform

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elight 2022年第1期2卷 132-142页

作者： Qian Ma Wei Gao Qiang Xiao lingsong Ding Tianyi Gao Yajun Zhou Xinxin Gao Tao Yan Che liu Ze Gu Xianghong Kong Qammer HAbbasi lianlin li Cheng‑Wei Qiu Yuanqing li Tie Jun Cui Institute of Electromagnetic Space Southeast UniversityNanjing 210096China School of Automation Science and Engineering South China University of TechnologyGuangzhou 510641China State Key Laboratory of Millimeter Wave Southeast UniversityNanjing 210096China Center of Intelligent Metamaterials Pazhou Laboratory Guangzhou 510330China Research Center for Brain-Computer Interface Pazhou LabGuangzhou 510330China Department of Electrical and Computer Engineering National University of SingaporeSingaporeSingapore University of Glasgow James Watt School of EngineeringGlasgow G128QQUK State Key Laboratory of Advanced Optical Communication Systems and Networks Department of ElectronicsPeking UniversityBeijing 100871China

Brain-computer interfaces(BCIs),invasive or non-invasive,have projected unparalleled vision and promise for assisting patients in need to better their interaction with the *** by the BCI-based rehabilitation technologies for nerve-system impairments and amputation,we propose an electromagnetic brain-computer-metasurface(EBCM)paradigm,regulated by human’s cognition by brain signals directly and *** experimentally show that our EBCM platform can translate human’s mind from evoked potentials of P300-based electroencephalography to digital coding information in the electromagnetic domain non-invasively,which can be further processed and transported by an information metasurface in automated and wireless *** wireless communications of the human minds are performed between two EBCM operators with accurate text ***,several other proof-of-concept mind-control schemes are presented using the same EBCM platform,exhibiting flexibly-customized capabilities of information processing and synthesis like visual-beam scanning,wave modulations,and pattern encoding.

关键词： communication computer surface