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Macroscopic model and statistical model to characterize electromagnetic information of a digital coding metasurface

National Science Review 2024年第3期11卷 159-171页

作者： Rui Wen Shao Jun Wei Wu Zheng Xing Wang Hui Xu Han Qing Yang Qiang Cheng Tie Jun Cui Institute of Electromagnetic Space Southeast University state key laboratory of millimeter waves Southeast University Peng Cheng laboratory Pazhou laboratory(Huangpu)

A digital coding metasurface is a platform connecting the digital space and electromagnetic wave space, and has therefore gained much attention due to its intriguing value in reshaping wireless channels and realizing new communication architectures. Correspondingly, there is an urgent need for electromagnetic information theory that reveals the upper limit of communication capacity and supports the accurate design of metasurface-based communication systems. To this end, we propose a macroscopic model and a statistical model of the digital coding metasurface. The macroscopic model uniformly accommodates both digital and electromagnetic aspects of the meta-atoms and predicts all possible scattered fields of the digital coding metasurface based on a small number of simulations or measurements. Full-wave simulations and experimental results show that the macroscopic model is feasible and accurate. A statistical model is further proposed to correlate the mutual coupling between meta-atoms with covariance and to calculate the entropy of the equivalent currents of digital coding metasurface. These two models can help reconfigurable intelligent surfaces achieve more accurate beamforming and channel estimation, and thus improve signal power and coverage. Moreover, the models will encourage the creation of a precoding codebook in metasurface-based direct digital modulation systems, with the aim of approaching the upper limit of channel capacity. With these two models, the concepts of current space and current entropy, as well as the analysis of information loss from the coding space to wave space, is established for the first time, helping to bridge the gap between the digital world and the physical world, and advancing developments of electromagnetic information theory and new-architecture wireless systems.

关键词： electromagnetic information theory current entropy current space digital coding metasurface macroscopic model statistical model

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A dual-band wireless communication of spoof plasmonic meta-waveguide

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Science China(Information Sciences) 2024年第7期67卷 337-338页

作者： Xinxin GAO Geng-Bo WU Ze GU Qian MA Wenyi CUI Tiejun CUI Chihou CHAN state key laboratory of terahertz and millimeter waves City University of Hong Kong state key laboratory of millimeter waves Southeast University Department of Electrical Engineering City University of Hong Kong

The ever-growing demands in wireless communications,computational imaging, and light detection necessitate the capability to freely manipulate electromagnetic waves.Miniaturized and highly integrated devices hold great promise for the future of communications. Spoof plasmonic metamaterials, in particular, have shown potential in creating functional devices and systems due to their ultracompact and low-profile advantages [1–3].

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A 26.5–29.5-GHz Doherty PA with enhanced linearity and efficiency based on adaptive bias circuit for 5G MIMO arrays

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Science China(Information Sciences) 2024年第7期67卷 341-342页

作者： Long WANG Jixin CHEN Debin HOU Xiaojie XU Wei HONG state key laboratory of millimeter waves Southeast University Misic Microelectronics Co. Ltd.

Power amplifiers (PAs) play a crucial role in achieving key performance metrics such as efficiency, power, and linearity.However, in the millimeter-wave frequency range, the performance of active devices rapidly deteriorates with increasing frequency. The typical Doherty architecture, through load modulation techniques, can achieve high back-off efficiency [1]. To enhance the linearity of the PA, adaptive bias circuits (ADBs) have been widely adopted [2, 3].

关键词： POWER-AMPLIFIER

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Multi-stream signals separation based on space-time-isomeric (SPATIO) array using metasurface antennas

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Science China(Information Sciences) 2024年第2期67卷 181-200页

作者： Yangming LOU Liang JIN Huiming WANG Zhou ZHONG Junyan DAI PLA Strategic Support Force Information Engineering University School of Information and Communications Engineering Xi'an Jiaotong University 3. State Key Laboratory of Millimeter WavesSoutheast University

In spatial domain signal processing, it is necessary to equip more antennas at the receiver to improve spatial demultiplexing capability. However, increasing the number of antennas under restricted space will reduce antenna spacing and raise the channel correlation, making the number of signal streams spatially demultiplexed much smaller than that of antennas. This paper proposes a method to design a space-timeisomeric(SPATIO) array based on metasurface antennas under wireless multipath conditions. Each antenna in this array has a different pattern and varies independently with time, reducing the channel correlation by superposing multipath at distinct positions and moments. Based on the SPATIO array, we present an array parameter design scheme based on infinity norm minimization, which can maximize the received energy of each stream while separating multi-stream received signals. Simulation results illustrate the performance of the SPATIO array for multi-stream signal reception. Compared with conventional multiple-input multipleoutput arrays, the proposed array can reduce the bit error rate by one order of magnitude under the same simulation conditions.

关键词： multiple-input multiple-output metasurface antenna space-time-isomeric array multipath channel degree of freedom

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An Ultra-wideband Doubler Chain With 43–65dBc Fundamental Rejection in Ku/K/Ka Band

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Chinese Journal of Electronics 2024年

作者： Long WANG Jixin CHEN Debin HOU Xiaojie XU Zekun LI Dawei TANG Rui ZHOU Hao QI Yu XIANG state key laboratory of millimeter waves Southeast University Misic Microelectronics Co.Ltd.

In this paper, a double-balanced doubler chain with >43-d Bc fundamental rejection over an ultra-wide bandwidth in 0.13-μm SiGe BiCMOS technology is proposed. To achieve high fundamental rejection, high output power, and high conversion gain over an ultra-wideband, a double-balanced doubler chain with pre-and post-drivers employs a bandwidth broadening technique and a ground shielding strategy. Analysis and comparison of single-balanced and double-balanced doublers were conducted, focusing on their fundamental rejection and circuit imbalance.Three doublers, a passive single-balanced doubler, an active single-balanced doubler, and a passive double-balanced doubler, were designed to verify the performance and characteristics of the single-and double-balanced doublers.Measurements show that the proposed double-balanced doubler chain has about 15-dB better fundamental rejection,and over more than twice the relative bandwidth compared to the single-balanced doubler chain fabricated with the same process. Over an 86.9% 3-dB bandwidth from 13.4 to 34 GHz, the double-balanced doubler chain delivers 14.7-d Bm peak output power and >43-/33-d Bc fundamental/third-harmonic rejection. To the authors' best knowledge, the proposed double-balanced doubler chain shows the highest fundamental rejection over an ultra-wideband among silicon-based doublers at millimeter-wave frequency bands.

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50-110 GHz,high isolation,and high-power linearity single-pole double-throw switch utilizing 100-nm GaN HEMT technology

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The Journal of China Universities of Posts and Telecommunications 2024年第2期31卷 38-43,71页

作者： Han Qunfei Hu Sanming Zhang Tianyu Chen Qing Shen Yizhu Wang Weibo Tao Hongqi School of Information Science and Engineering Southeast UniversityNanjing 210096China Nanjing Electronic Devices Institute Nanjing 210016China state key laboratory of millimeter waves Southeast UniversityNanjing 210096China

This article presents the design and performance of a single-pole double-throw(SPDT)switch operating in 50-110 GHz.The switch is fabricated in a 100-nm GaN high-electron-mobility transistors(HEMT)technology.To realize high-power capability,the dimensions of GaN HEMTs are selected by simulation verification.To enhance the isolation,an improved structure of shunt HEMT with two ground holes is employed.To extend the operation bandwidth,the SPDT switch with multi-section resonant units is proposed and analyzed.To verify the SPDT switch design,a prototype operating in 50-110 GHz is fabricated.The measured results show that the fabricated SPDT switch monolithic microwave integrated circuit(MMIC)achieves an input 1 dB compression point(P_(1dB))of 38 dBm at 94 GHz,and isolation within the range of 33 dB to 54 dB in 50-110 GHz.The insertion loss of the switch is less than 2.1 dB,while the voltage standing wave ratios(VSWR)of the input port and output port are both less than 1.8 in the operation bandwidth.Based on the measured results,the presented SPDT switch MMIC demonstrates high power capability and high isolation compared with other reported millimeter-wave SPDT MMIC designs.

关键词： GaN high-electron-mobility transistors(HEMT) millimeter-wave single-pole double-throw(SPDT) switch

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Performance Analysis of Spatial Modulation Aided UAV Communication Systems in Cooperative Relay Networks

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Chinese Journal of Electronics 2024年

作者： Xiangbin YU Mingfeng XIE Ning LI Cuimin PAN College of Electronic and Information Engineering Nanjing University of Aeronautics and Astronautics state key laboratory of millimeter waves Southeast University

In this paper, by introducing the spatial modulation(SM) scheme into the unmanned aerial vehicle(UAV) relaying system, a SM-aided UAV(SM-UAV) cooperative relay network is presented. The performance of the SM-UAV relay network is investigated over Nakagami-m fading channels, where the UAV remains stationary over a given area. According to the performance analysis, using the amplify-and-forward(AF) protocol, the effective signalto-noise ratio(SNR) and the corresponding probability density function and moment generating function are, respectively, derived. With these results, the average bit error rate(BER) is further deduced, and resultant approximate closed-form expression is achieved. Based on the approximate BER, we derive the asymptotic BER to characterize the error performance of the system at high SNR. With this asymptotic BER, the diversity gain of the system is derived, and the resulting diversity order is attained. Simulation results illustrate the effectiveness of the performance analysis. Namely, approximate BER has the value close to the simulated one, and asymptotic BER can match the corresponding simulation well at high SNR. Thus, the BER performance of the system can be effectively assessed in theory, and conventional simulation will be avoided. Besides, the impacts of the antenna number, modulation order,fading parameter and UAV position on the system performance are also analyzed. The results indicate that the BER performance is increased with the increases of Nakagami parameter m and/or receive antenna and/or the decrease of modulation order.

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Microstructured fluorescence in liquid crystals with femtosecond laser excitation

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Chinese Optics Letters 2024年第3期22卷 154-158页

作者：孟霞金萍葛士军刘娇李炳祥王磊陆延青 College of Electronic and Optical Engineering&College of Flexible Electronics(Future Technology) Nanjing University of Posts and TelecommunicationsNanjing 210023China National laboratory of Solid state Microstructures College of Engineering and Applied SciencesNanjing UniversityNanjing 210093China state key laboratory of millimeter waves Southeast UniversityNanjing 210096China

This study investigated direct fluorescence generation from a nematic liquid crystal(NLC)NJU-LDn-4 under femtosecond laser excitation.The absorption,transmittance,excitation,and emission spectra of the NLC were assessed.The relationship between the femtosecond pump power and fluorescence intensity was analyzed,revealing a quadratic increase and indicating that two-photon absorption(2PA)is the primary fluorescence mechanism.The LC microstructure was designed using photoalignment technology,allowing the generated fluorescence to reflect the corresponding structure.This research can establish a foundation for tunable LC microstructured fluorescence,with potential applications in fluorescence microscopy and optoelectronics.

关键词： liquid crystal femtosecond laser fluorescence microstructure

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Miniature tunable Airy beam optical meta-device

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Opto-Electronic Advances 2024年第2期7卷 5-12页

作者： Jing Cheng Zhang Mu Ku Chen Yubin Fan Qinmiao Chen Shufan Chen Jin Yao Xiaoyuan Liu Shumin Xiao Din Ping Tsai Department of Electrical Engineering City University of Hong KongKowloonHong Kong SAR 999077China state key laboratory of terahertz and millimeter waves City University of Hong KongKowloonHong Kong SAR 999077China Centre for Biosystems Neuroscienceand NanotechnologyCity University of Hong KongKowloonHong Kong SAR 999077China Ministry of Industry and Information Technology key Lab of Micro-Nano Optoelectronic Information System Guangdong Provincial Key Laboratory of Semiconductor Optoelectronic Materials and Intelligent Photonic SystemsHarbin Institute of TechnologyShenzhen 518055China

Tunable Airy beams with controllable propagation trajectories have sparked interest in various fields,such as optical manipulation and laser fabrication.Existing research approaches encounter challenges related to insufficient compactness and integration feasibility,or they require enhanced tunability to enable real-time dynamic manipulation of the propagation trajectory.In this work,we present a novel method that utilizes a dual metasurface system to surpass these limitations,significantly enhancing the practical potential of the Airy beam.Our approach involves encoding a cubic phase profile and two off-axis Fresnel lens phase profiles across the two metasurfaces.The validity of the proposed strategy has been confirmed through simulation and experimental results.The proposed meta-device addresses the existing limitations and lays the foundation for broadening the applicability of Airy beams across diverse domains,encompassing light-sheet microscopy,laser fabrication,optical tweezers,etc.

关键词： metasurface miniature device tunable Airy beam tunable meta-device

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基于5 μm厚向列相液晶的高效圆极化相控阵系统的设计、校准和实验验证

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Engineering 2024年第1期32卷 69-81页

作者： Xin Yu Wu Fengshuo Wan Hongyuan Feng Shichao Jin Chong Guo Yu Wei Dunge Liu Yuqian Yang Longzhu Cai Zhi Hao Jiang Wei Hong state key laboratory of millimeter waves School ofInformation Science and Engineering Southeast UniversityNanjing 210096China state key laboratory of Space-Ground Integrated Information Technology Beijing Institute of Satellite Information Engineering Beijing 100095China Research Institute of millimeter-Wave and terahertz Technology(RIMMATT) Nanjing 211111China

This paper presents a systematic investigation and demonstration of a K-band circularly polarized liquidcrystal-based phased array(LCPA),including the design,over-the-air(OTA)in-array calibration,and experimental validation.The LCPA contains 16 phase-shifting radiating channels,each consisting of a circularly polarized stacked patch antenna and a liquid-crystal-based phase shifter(LCPS)based on a loaded differential line structure.Thanks to its slow-wave properties,the LCPS exhibits a maximum phase-shifting range of more than 360°with a figure of merit of 78.3(°)·dB^(-1)based on a liquid crystal layer with a thickness of only 5μm.Furthermore,an automatic OTA calibration based on a state ergodic method is proposed,which enables the extraction of the phase-voltage curve of every individual LCPA channel.The proposed LCPA is manufactured and characterized with a total profile of only 1.76 mm,experimentally demonstrating a scanned circularly polarized beam from-40°to+40°with a measured peak gain of 12.5 dBic and a scanning loss of less than 2.5 dB.The bandwidth of the LCPA,which satisfies the require-ments of port reflection(|S_(11)|)state of the art.The use of the demonstrated low-profile LCPA to support circularly polarized scanning beams,along with the systematic design and calibration methodology,holds potential promise for a variety of millimeter-wave applications.

关键词： Circularly polarized Liquid crystal Liquid-crystal based phased array(LCPA) Phase shifter Over-the-air(OTA)calibration

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