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A Reflectarray With Low Profile Based on the Method of Choosing the Certain Phase Constant

IEEE Antennas and Wireless Propagation Letters 2025年第6期24卷 1397-1401页

作者： Li, Wenting Lin, Wenting Li, Ruiyang He, Yejun Gao, Yao Zhang, Chong Gao, Steven State Key Laboratory of Radio Frequency Heterogeneous Integration School of Electronic and Information Engineering Shenzhen University Shenzhen China School of Electrical and Information Engineering Zhengzhou University Zhengzhou China School of Information Engineering Chang'an University Xi'an China School of Information Science and Engineering Shenyang University of Technology Shenyang China Department of Electronic Engineering Chinese University of Hong Kong Hong Kong China

In this letter, a reflectarray antenna with a small focal diameter ratio (F\D) is presented. It is found that when the F\D is extremely small, the phase constant used in calculating the required reflection phase on the reflecting surface significantly affects the radiation pattern. In certain cases, an unsuitable phase constant can even cause the main beam to split. The unit cell is implemented as a stacked patch, and the reflecting surface comprises 14 × 14 elements. The effect of the phase constant on the radiation pattern is analyzed, and two reflectarrays with phase constants of 90° and 180°, both operating at 10 GHz with an F\D of 0.05, are compared. These two reflectarrays are simulated, fabricated, and measured. The measured results show good agreement with the simulations. Within the operating band, the reflectarray with a phase constant of 90° achieves a maximum measured gain of 20.42 dBi, with the first sidelobe level (SLL1) below -10 dB. The radiation pattern of the reflectarray with a phase constant of 180° is totally distorted, resulting in a measured gain of 6.56 dBi at 10 GHz and an SLL1 of -5.8 dB. © 2002-2011 IEEE.

关键词： Reflection

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Enhancing Offensive Language Detection with Data Augmentation and Knowledge Distillation

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Research 2024年第2期6卷 29-40页

作者： Jiawen Deng Zhuang Chen Hao Sun Zhexin Zhang Jincenzi Wu Satoshi Nakagawa Fuji Ren Minlie Huang The CoAl group DCSTInstitute for Artificial InteligenceState Key Lab of Intelligent Technology and SystemsBeijing National Research Center for Information Science and TechnologyTsinghua UniversityBeijing 100084China Graduate School of Information Science&Technology The University of Tokyo.Tokyo 1138654Japan School of Computer Science and Engineering University of Electronic Science and Technology of ChinaChengduSichuan611731China

Offensive language detection has received important attention and plays a crucial role in promoting healthy communication on social platforms,as well as promoting the safe deployment of large language *** data is the basis for developing detectors;however,the available offense-related dataset in Chinese is severely limited in terms of data scale and coverage when compared to English *** significantly affects the accuracy of Chinese offensive language detectors in practical applications,especially when dealing with hard cases or out-of-domain *** alleviate the limitations posed by available datasets,we introduce AugCOLD(Augmented Chinese Offensive Language Dataset),a large-scale unsupervised dataset containing 1 million samples gathered by data crawling and model ***,we employ a multiteacher distillation framework to enhance detection performance with unsupervised *** is,we build multiple teachers with publicly accessible datasets and use them to assign soft labels to *** soft labels serve as a bridge for knowledge to be distilled from both AugCOLD and multiteacher to the student network,i.e.,the final offensive *** conduct experiments on multiple public test sets and our well-designed hard tests,demonstrating that our proposal can effectively improve the generalization and robustness of the offensive language detector.

关键词： COLD dealing limitations

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Two efficient beamforming methods for hybrid IRS-aided AF relay wireless networks

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science China(information sciences) 2025年第4期68卷 363-379页

作者： Xuehui WANG Qingbo LI Wen ZHU Feng SHU Mengxing HUANG Fuhui ZHOU Riqing CHEN Cunhua PAN Yongpeng WU Jiangzhou WANG School of Mathematics and Statistics Hainan Normal University Key Laboratory of Data Science and Smart Education Ministry of Education Hainan Normal University School of Information and Communication Engineering Hainan University Collaborative Innovation Center of Information Technology Hainan University School of Electronic and Optical Engineering Nanjing University of Science and Technology College of Electronic and Information Engineering Nanjing University of Aeronautics and Astronautics Digital Fujian Institute of Big Data for Agriculture Fujian Agriculture and Forestry University National Mobile Communications Research Laboratory Southeast University Shanghai Key Laboratory of Navigation and Location Based Services Shanghai Jiao Tong University School of Engineering University of Kent

Owing to its ability to mitigate the double-fading effect by amplifying the reflected signal, the active intelligent reflecting surface(IRS) has garnered significant attention. In this paper, an amplify-and-forward(AF) relay network assisted by a hybrid IRS consisting of both passive and active units is developed. A signal-to-noise ratio(SNR) maximization problem is formulated, where the AF relay beamforming matrix and the hybrid IRS reflecting coefficient matrices for two-time slots need to be optimized. To address the SNR maximization problem, this paper proposes both a high-performance(HP) method and a low-complexity(LC) method. The HP method is based on the semidefinite relaxation and fractional programming(SDR-FP)algorithm, with rank-1 solutions obtained through Gaussian randomization. For the LC method, the amplification coefficient of each active IRS element is assumed to be equal. The SNR maximization problem is then addressed using the whitening filter,generalized power iteration, and generalized Rayleigh-Ritz(WF-GPI-GRR) approach. Simulation results show that compared with the benchmarks, such as the passive IRS-aided AF relay network, the proposed HP-SDR-FP and WF-GPI-GRR methods achieve significant rate improvements. In particular, the HP-SDR-FP and WF-GPI-GRR methods yield more than a 135.0%rate gain when the transmit power Ps of the source is 10 dBm. Furthermore, the proposed HP-SDR-FP method outperforms the WF-GPI-GRR method in terms of rate performance.

关键词： double-fading intelligent reflecting surface active elements passive elements hybrid IRS AF relay

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Research on RCS Data Validation Based on SPWVD

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Progress In Electromagnetics Research C 2024年 144卷 147-158页

作者： Shi, Jiaxin Hu, Jun Gao, Zhiwei Song, Lizhong Zhao, Huapeng Zhao, Ran Chen, Wei Zhang, Min School of Information Science and Engineering Harbin Institute of Technology at Weihai Weihai China University of Electronic Science and Technology of China Chengdu China School of Information Science and Technology Shijiazhuang Tiedao University Shijiazhuang China National Key Laboratory of Air-based Information Perception and Fusion China

At present, Feature Selective Validation (FSV) is the most common data verification method of computational electromagnetics, and its effectiveness has been verified since its release in 2006, but since the main research object of this method is electromagnetic compatibility data, the 8 sets of data used for algorithm training also come from the field of electromagnetic compatibility, and its data curve has the characteristics of gentle waveform and small fluctuations. However, Radar Cross Section (RCS) data, especially high-frequency RCS data, usually have complex waveforms and drastic fluctuations, and the results obtained by the FSV method are often quite different from those obtained by experts. This paper proposes a new data verification method based on Smoothed Pseudo Wigner-Ville Distribution (SPWVD) algorithm for RCS data, which integrates the characteristics of RCS data and expert evaluation experience, and verifies its effectiveness in RCS data verification. © 2024, Electromagnetics Academy. All rights reserved.

关键词： Radar cross section

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Van der Waals epitaxial growth of single-crystal molecular film

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National science Review 2024年第11期11卷 194-202页

作者： Lixin Liu Penglai Gong Kailang Liu Bingrong Huang Zhihao Zhang Yingshuang Fu Yu Wu Yinghe Zhao Meihui Wang Yongshan Xu Huiqiao Li Tianyou Zhai State Key Laboratory of Materials Processing and Die &Mould Technology School of Materials Science and EngineeringHuazhong University of Science and Technology Key Laboratory of Optic-Electronic Information and Materials of Hebei Province College of Physics Science and Technology Hebei University Wuhan National High Magnetic Field Center School of Physics Huazhong University of Science and Technology

Epitaxy is the cornerstone of semiconductor technology, enabling the fabrication of single-crystal *** advancements in van der Waals（vd W） epitaxy have opened new avenues for producing wafer-scale single-crystal 2D atomic crystals. However, when it comes to molecular crystals, the overall weak vd W force means that it is a significant challenge for small molecules to form a well-ordered structure during *** we demonstrate that the vd W epitaxy of Sb2O3molecular crystal, where the whole growth process is governed by vd W interactions, can be precisely controlled. The nucleation is deterministically modulated by epilayer–substrate interactions and unidirectional nuclei are realized through designing the lattice and symmetry matching between epilayer and substrate. Moreover, the growth and coalescence of nuclei as well as the layer-by-layer growth mode are kinetically realized via tackling the Schwoebel-Ehrlich barrier. Such precise control of vd W epitaxy enables the growth of single-crystal Sb2O3molecular film with desirable thickness. Using the ultrathin highly oriented Sb2O3film as a gate dielectric, we fabricated MoS2-based field-effect transistors that exhibit superior device performance. The results substantiate the viability of precisely managing molecule alignment in vd W epitaxy, paving the way for large-scale synthesis of single-crystal 2D molecular crystals.

关键词： van der Waals epitaxy inorganic molecular crystal layer-by-layer growth single-crystal film dielectric

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Safety-Critical Parallel Trajectory Tracking Control of Maritime Autonomous Surface Ships Based on Integral Control Barrier Functions

IEEE Transactions on Intelligent Vehicles

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IEEE Transactions on Intelligent Vehicles 2024年第5期9卷 1-10页

作者： Xu, Jiaxue Gu, Nan Wang, Dan Li, Tieshan Han, Bing Peng, Zhouhua School of Marine Electrical Engineering Dalian Maritime University Dalian China School of Automation Engineering University of Electronic Science and Technology of China Chengdu China College of Physics and Electronic Information Engineering Minjiang University Fujian China

This article investigates the parallel trajectory tracking control of fully-actuated maritime autonomous surface ships (MASSs) in the presence of multiple stationary/moving ocean obstacles. A safety-critical parallel control architecture is proposed for the trajectory tracking control of MASSs. Specifically, an artificial MASS system is constructed based on a data-driven learning predictor where real-time and historical navigation data are both utilized to achieve the estimation of the unknown weights of Taylor polynomials and Fourier series. Then, a parallel trajectory tracking control law is designed based on the artificial system such that the MASS is capable of track the reference trajectory positively. Finally, integral control barrier functions are employed to encode input and safety constraints. A safety optimization signal is augmented to the designed parallel control law to achieve the collision avoidance of all ocean obstacles. Based on the stability and safety analyses, the tracking errors of the actual MASS system are verified to be uniformly ultimately bounded and the MASS system is safe. Numerical examples confirm the effectiveness of the designed safety-critical parallel trajectory tracking control scheme for the MASS. IEEE

关键词： Trajectories

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Adaptive Intelligent Control-Based Consensus Tracking for a Class of Switched Nonstrict Feedback Nonlinear Multiagent Systems With Unmodeled Dynamics

IEEE Transactions on Artificial Intelligence

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IEEE Transactions on Artificial Intelligence 2024年第4期5卷 1624-1634页

作者： Niu, Ben Liu, Xinyu Guo, Zhihua Jiang, Hao Wang, Huanqing Dalian University of Technology Faculty of Electronic Information and Electrical Engineering Dalian116024 China Shandong Normal University School of Information Science and Engineering Jinan250014 China Bohai University School of Mathematics Science Jinzhou121000 China

Based on the adaptive intelligent control technique, we develop an adaptive consensus tracking control scheme for the distributed switched nonstrict feedback nonlinear multiagent systems (MASs) with unmodeled dynamics. According to the properties of Gaussian functions, a fresh scheme is utilized to handle the nonstrict feedback form. Based on the characters of unmodeled dynamics, a dynamic signal is designed to resolve the design difficulties caused by the unmodeled dynamics. In the design process of the adaptive switching controllers, the backstepping technique is adopted and the unknown nonlinear functions are estimated by utilizing the radial basis function neural networks' intelligent technique. Besides, a common Lyapunov function is constructed to analyze the system's stability. Under the Lyapunov stability theory, it is rigorously demonstrated that all signals of the closed-loop switched MAS are cooperatively semiglobal uniformly ultimately bounded and the outputs of all the followers eventually track the leader's output. Finally, the simulation results of a practical example is presented to confirm the efficiency of the proposed control scheme. © 2020 IEEE.

关键词： Multi agent systems

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Research Progress on Sub-band Fusion technology for Ultra-wideband Radar Signals

Research Progress on Sub-band Fusion Technology for Ultra-wi...

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2024 Photonics and Electromagnetics Research Symposium, PIERS 2024

作者： Huang, Denghui Zhang, Ying Zhao, Huapeng He, Muchen Wang, Yipeng Qin, Xinxin University of Electronic Science and Technology of China School of Information and Communication Engineering Chengdu China University of Electronic Science and Technology of China School of Electronic Science and Engineering Chengdu China

ISBN: (纸本)9798350375909

Ultra-wideband signal which improves radar range resolution and facilitates target recognition is attractive in radar applications. However, it is expensive and unrealistic to construct ultra-wideband radar hardware. Therefore, sub-band fusion technology becomes an alternative because of its low construction cost and high computation accuracy. Sub-band fusion technology involves several key procedures, including sub-band fitting, multi-band coherent processing, and ultra-wideband extrapolation. For sub-band fitting, several existing electromagnetic scattering models can be used and their parameters are extracted using parameter estimation algorithms. It is noted that system errors and asynchronization between sub-bands cause incoherence between multi-bands. To compensate incoherence between multi-bands, sub-bands are extrapolated and a mutual coherence model should be constructed and estimated so that coherence between multi-bands can be restored. Finally, ultra-wideband extrapolation is realized by joint processing of coherent multi-bands. In this paper, research progress on the aforementioned procedures is summarized. Performance of existing algorithms are analyzed and compared. Finally, multi-band fusion results based on simulated data as well as static-range data and future discussion are presented. © 2024 IEEE.

关键词： Extrapolation

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OTFS on Overspread Doubly Selective Channel

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China Communications 2024年第11期21卷 205-215页

作者： Qing Hua Liu Yun Shi Xiayang Yu Hua Ji Fei Cui Yinming College of Software Engineering Zhengzhou University of Light IndustryZhengzhou 450002China School of Internet Finance and Information Engineering Guangdong University of FinanceGuangzhou 510520China School of Electronic and Information Engineering South China University of TechnologyGuangzhou 510641China

The orthogonal time frequency space(OTFS)modulation proposed in recent years is considered to have superior performance than orthogonal frequency division multiplexing(OFDM)for the doubly selective(DS)*** works in the existing literature on OTFS mainly focus on the cases where the channels are underspread(i.e.,the product of the delay spread and the Doppler spread is less than 1).In the scenario of overspread DS channel,which has large delay spread and severe Doppler spread,such as underwater acoustic(UWA)channel,the channel model in delay-Doppler(DD)Domain derived by existing work is no longer *** this paper,we derive a more generalized expression of the channel model in delay-Doppler domain,which allows the product of the delay spread and Doppler spread to be larger *** result shows that the existing channel model is just a special case of the one we *** the proposed channel matrix in DD domain,we build the OTFS detectors with the minimum mean square error(MMSE)and message passing(MP)algorithms on overspread doubly selective ***,simulation results are presented to verify the theoretical derivation and the effectiveness of the detectors.

关键词： delay-Doppler domain doubly selective channel OTFS overspread underwater acoustic communications

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Design of Fixed-point FFT Algorithm Based on Memristor 4

Design of Fixed-point FFT Algorithm Based on Memristor

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4th International Conference on Computers and Artificial Intelligence technology, CAIT 2023

作者： Zhou, Zhexian Zhong, Xuefeng Yu, Yongbin Wang, Xiangxiang Feng, Xiao Shen, Jiarun Tashi, Nyima University of Electronic Science and Technology of China School of Information and Software Engineering Chengdu China Tibet University School of Information Science and Technology Lhasa China

ISBN: (纸本)9798350326710

This study introduces a novel approach, leveraging memristor-based fixed-point computing, to implement a high-performance Fast Fourier Transform (FFT) algorithm. Memristors enable direct data processing within memory, addressing power inefficiencies and processing bottlenecks associated with conventional architectures. The proposed method emphasizes parallelism through memristor calculations, enhancing computational efficiency in resource-constrained environments. In the image processing and restoration algorithms, the Memristor-based Fixed-point FFT demonstrates both efficacy and accuracy. Despite precision constraints in memristor-based fixed-point FFT, normalization strategies effectively mitigate noise in image transformations. © 2023 IEEE.

关键词： Memristors

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