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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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Wideband Circularly Polarized Substrate-Integrated Waveguide Aperture-Coupled Metasurface Antenna Array for millimeter-Wave Applications

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Chinese Journal of Electronics 2024年

作者： Jiwei LIAN Chun GENG Xue LU Dazhi DING School of Microelectronics (School of Integrated Circuits) Nanjing University of Science and Technology state key laboratory of millimeter waves Southeast University Qian Xuesen College Nanjing University of Science and Technology

A wideband circularly polarized(CP) aperture-coupled metasurface antenna operating at millimeterwave frequency spectrum in substrate-integrated waveguide(SIW) technology is proposed. Such a proposed metasurface antenna is composed of two substrates. The first substrate contains an end-shorted SIW section with a slot etched. The introduced metasurface is printed on the top of the second substrate. The metasurface is comprised of3 × 3 unit cells, each of which contains two interconnected patches and two parasitic patches. The working mechanism of the proposed metasurface antenna is illustrated in details. The proposed metasurface antenna has wide impedance bandwidth and axial ratio(AR) bandwidth, which are 66.7% and 40%, respectively. Using the proposed metasurface antenna, a 4 × 4 CP metasurface antenna array with an impedance bandwidth of 24%, an AR bandwidth of 30%, and a peak gain of 18.7 dBic in simulation is developed in this paper for millimeter-wave applications.

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Full-parameter omnidirectional transformation optical devices

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National Science Review 2024年第3期11卷 92-99页

作者： Yuan Gao Yu Luo Jingjing Zhang Zhengjie Huang Bin Zheng Hongsheng Chen Dexin Ye Interdisciplinary Center for Quantum Information State Key Laboratory of Extreme Photonics and InstrumentationZJU-Hangzhou Global Scientific and Technological Innovation CenterZhejiang University School of Electrical and Electronic Engineering Nanyang Technological University CNRS-InternationalNTU-Thales Research Alliance Nanyang Technological University Institute of Electromagnetic Space Southeast University state key laboratory of millimeter waves Southeast University International Joint Innovation Center The Electromagnetics Academy at Zhejiang University Zhejiang University key laboratory of Advanced Micro/Nano Electronic Devices&Smart Systems of Zhejiang Jinhua Institute of Zhejiang UniversityZhejiang University Shaoxing Institute of Zhejiang University Zhejiang University

Transformation optics(TO) provides an unprecedented technique to control electromagnetic(EM) waves by engineering the constitutive parameters of the surrounding medium through a proper spatial transformation. In general, ideal transformation optical devices require simultaneous electric and magnetic responses along all three dimensions. To ease the practical implementation, previous studies usually made use of reduced parameters or other simplified approaches, which inevitably introduce extra reflection or unwanted phase shift. Up to today, experimental realizations of full-parameter transformation optical devices in free space are still quite limited. Here, a general design strategy is proposed to solve this problem.As a specific example, a full-parameter spatial-compression TO medium with constitutive parameters taking the diagonal form diag(a, a, 1/a) for the TM wave incidence was designed and realized experimentally. Such spatial-compression TO media were then applied to the implementation of an ideal omnidirectional invisibility cloak capable of concealing a large-scale object over a wide range of illumination angles. Both the simulation and experiment confirm that the cloak allows for nearly unity transmission of EM waves in the forward direction without introducing extra scattering or phase shift. This work constitutes an important stepping stone for future practical implementation of arbitrary full-parameter omnidirectional transformation optical devices.

关键词： transformation optical devices omnidirectional impedance matching full-parameter invisibility cloak

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