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关键词： Broadband antennas   Metasurfaces   Radiofrequency identification   Antenna measurements   Slot antennas   Antennas   Antenna arrays   Antenna radiation patterns   Gain   Broadband communication   RFID   reader   broadband   circular polarization   metasurface   antenna  

摘要： A low-profile broadband antenna with high-gain circularly polarized (CP) radiation is proposed for ultra-high frequency (UHF) radio frequency identification (RFID) readers. The design is a sequentially rotated 2 x 2 CP slot array. Each slot element utilizes two 45 degrees-rotated stubs to introduce proper structural asymmetry, and consequently, achieve CP radiation. The array is fed by a sequential-phase feeding network for improving CP radiation in terms of gain and 3-dB axial ratio (AR) bandwidth. For a broadside radiation, the slot array is backed by a ground plane (GND). A metasurface, which is composed of 6x6 periodic metallic plates, is inserted between the array and GND to allow a low profile with high efficiency. The final design with overall size of 210x210x32.4 mm(3) ( 0.6 lambda x 0.6 lambda x 0.09 lambda at 0.86 GHz) has been fabricated and measured. The measurements result in a 10-dB return-loss bandwidth of 0.81-0.96 GHz, a 3-dB AR bandwidth of 0.86-0.93 GHz, and broadside right-hand CP radiation with the peak gain of 8.7 dBic.

关键词： category information sampling   execution time   lower bound   near-optimal protocol   RFID systems  

摘要： In many RFID-enabled applications, objects are classified into different categories, and the information associated with each object's category (called category information) is written into the attached tag, allowing the reader to access it later. The category information sampling in such RFID systems, which is to randomly choose (sample) a few tags from each category and collect their category information, is fundamental for providing real-time monitoring and analysis in RFID. However, to the best of our knowledge, two technical challenges, i.e., how to guarantee a minimized execution time and reduce collection failure caused by missing tags, remain unsolved for this problem. In this paper, we address these two limitations by considering how to use the shortest possible time to sample a different number of random tags from each category and collect their category information sequentially in small batches. In particular, we first obtain a lower bound on the execution time of any protocol that can solve this problem. Subsequently, we present a near-OPTimal Category information sampling protocol (OPT-C) that solves the problem with an execution time close to the lower bound. Finally, extensive simulation results demonstrate the superiority of OPT-C over existing protocols, while real-world experiments further validate its practicality. © 2002-2012 IEEE.

关键词： 射频识别技术   血液保障   应用   标准   建议  

摘要： 该文系统梳理了射频识别技术在血液全流程管理中的研究进展与应用实践，重点从献血者管理、体检初筛、血液采集与检验、成分制备、血液出入库、临床输血管理等血液保障的关键环节深入分析该技术的具体应用场景与实施效果。在全面总结当前血液保障相关技术应用成效与存在瓶颈的基础上，进一步提出了射频识别技术在血液供应保障管理中的优化方向与发展建议，旨在为构建智能化、可追溯的现代血液管理体系提供参考。

关键词： 射频识别   无线感知   手势识别   深度学习   无线信号  

摘要： 阐述一种基于射频识别技术（RFID）的动态手势识别系统。实验设计了信号数据预处理方法，以减少环境噪声的干扰，并采用双输入卷积神经网络进行手势特征提取和分类。该方法在采集的手势数据集上实现了97.8%的识别准确率，优于现有方法，实验验证了该系统的有效性和可行性。

关键词： postquantum cryptography   lattice-based authentication scheme   IoT   RFID   anonymity  

摘要： The Internet of Things (IoT) comprises a complex network of smart objects that collect and exchange data with each other via the public Internet. Radio-frequency identification (RFID) technology is currently one of the most important IoT technologies. To achieve the goal of intelligent management of items, radio-frequency identification tags retain messages gathered by the reader before transmitting them to the backend system processing and analysis. This creates a vast knowledge network. Considering that, personal information and privacy exposure, malicious tracking, and counterfeiting behaviours remain unresolved issues in the security area, we provide a lattice-based authentication technique in this research. The proposed lattice-based lightweight anonymous authentication protocol (LBAA) was based on the Inhomogeneous Small Integer Solution (ISIS) problem, which aids in resistance to quantum attacks. Additionally, the features of unforgeability, scalability, mutual authentication, availability, and perfect forward secrecy were attained. LBAA protocol offered anonymity and untraceability to both an adversary and an honest-but-curious backend server. The suggested approach provided defence against man-in-the-middle attacks tags collaboration attacks desynchronization attacks, track and trace attacks, and replay and impersonation attacks. To achieve this, we analyse the proposed protocol using both informal and formal analysis methods, such as the Real-or-Random (ROR) model and Scyther tools. Additionally, effectiveness of the proposed technique was compared to current studies.

关键词： RFID tags   Sensors   Impedance   Antennas   Biomedical monitoring   Reflection coefficient   Substrates   Monitoring   Fabrication   Dipole antennas   RFID sensor   meander resonator   antenna sensing   wearable sensing   biomechanics sensing   displacement sensing   knee flexion  

摘要： This paper presents a biomechanics sensing system based on an ultra-high frequency (UHF) RFID tag coupled with a meander resonator for motion tracking and displacement sensing. The variations in their relative position alter the strength of mutual coupling, leading to impedance changes in the RFID tag antenna. These impedance variations modulate the power reflection coefficient, which in turn affects both the backscattered signal strength (RSSI) and the turn-on threshold power of the RFID tag. The performance of the system was evaluated through simulations and experimental validation, demonstrating a 14 dB reduction in RSSI and a 5 dBm increase in threshold power over a displacement range of 30 mm. The system was further validated for wearable movement sensing in knee flexion tracking, where results indicated an RSSI variation of around 12 dB as the knee angle changed from 115 degrees to 175 degrees. Additionally, the turn-on threshold power (P-th) exhibited a strong correlation with knee flexion angles, achieving a coefficient of determination (R-2 = 0.973) based on curve-fitted data. These results validate the feasibility of the proposed system for wearable body motion monitoring in healthcare applications.

关键词： Reliability   Backscatter   Receivers   Symbols   Reliability theory   Prototypes   Radiofrequency identification   Scalability   Costs   Bandwidth   Backscatter network   receiver-less tags   reliability   RFID   passive IoT  

摘要： Backscatter radio is a promising technology for low-cost and low-power Internet-of-Things (IoT) networks. The conventional monostatic backscatter radio is constrained by its limited communication range, which restricts its utility in wide-area applications. An alternative bi-static backscatter radio architecture, characterized by a dis-aggregated illuminator and receiver, can provide enhanced coverage and, thus, can support wide-area applications. In this paper, we analyze the scalability of the bi-static backscatter radio for large-scale wide-area IoT networks consisting of a large number of unsynchronized, receiver-less tags. We introduce the Tag Drop Rate (TDR) as a measure of reliability and develop a theoretical framework to estimate TDR in terms of the network parameters. We show that under certain approximations, a small-scale prototype can emulate a large-scale network. We then use the measurements from experimental prototypes of bi-static backscatter networks (BNs) to refine the theoretical model. Finally, based on the insights derived from the theoretical model and the experimental measurements, we describe a systematic methodology for tuning the network parameters and identifying the physical layer design requirements for the reliable operation of large-scale bi-static BNs. Our analysis shows that even with a modest physical layer requirement of bit error rate (BER) 0.2, 1000 receiver-less tags can be supported with 99.9% reliability. This demonstrates the feasibility of bi-static BNs for large-scale wide-area IoT applications.

关键词： Dual band   Radiofrequency identification   Dipole antennas   Antennas   Polarization   Bandwidth   Antenna measurements   UHF antennas   Reflection   Reliability   metasurfaces   multifrequency antennas   radiofrequency identification  

摘要： RFID systems often fail to detect tags due to polarization mismatch, interference, and blind spots caused by obstructed tags in dense metallic environments with multipath effects. This study addresses these issues by developing a dual-band circularly polarized (CP) RFID reader antenna equipped with an artificial magnetic conductor (AMC) for unidirectional radiation, alongside a blind spot mitigation metasurface (BSMM) to improve detection coverage. The AMC operates at both ultra-high frequency (UHF) and microwave bands, supporting the antenna's dual-band design and stable CP. The BSMM is a passive electromagnetic surface that operates independently of the reader antenna and is designed to redirect incident signals toward unread tags in shadowed regions, thereby mitigating blind spots in RFID detection. Experimental results show that the dual-band system achieves up to a 48% increase in read reliability at 200 cm compared to single-band systems. The AMC-backed antenna improves detection rates by up to 34% over a conventional cross-dipole design. The BSMM further removes detection failures, achieving 100% reliability at 50 cm and maintaining 80% at 100 cm. These findings demonstrate that the proposed antenna and BSMM significantly enhance RFID performance in real-world scenarios, enabling more robust item-level tracking.

关键词： storm drains   wastewater   RFID   radio frequency identification   unauthorized connections   protection of water bodies   state environmental control   discharges from industrial enterprises  

摘要： The paper presents the results of research on using radio frequency identification (RFID) technologies to prevent pollution by enabling early detection of industrial discharges. The goal of the study is to develop a method for detecting unauthorized connections to storm sewers using passive RFID technology. The authors justify the choice of passive RFID, based on the EPC Class 1 Gen2 standard (ISO/IEC 18000-63:2021(E)). The authors describe experiments to reliably detect RFID tags floating in protective casings on the water's surface by reader with the antenna positioned 0.5-1.5 m above the water. A key challenge is the difficulty in reading tags directly on the water's surface, as water shields and reflects the reader's electromagnetic waves. Additional tests were conducted to evaluate the impact of tag collisions on the accuracy and completeness of readings, as these collisions may cause missed tags when passing by the reader's antenna. The study confirms that passive RFID can address key challenges in detecting unauthorized storm sewer connections. RFID technology has the potential to improve the efficiency and accuracy of environmental monitoring, reduce control costs, and better protect water bodies from industrial pollution. The research is significant for advancing new methods and technologies in environmental protection and can be applied in state environmental control systems to identify and prevent unauthorized wastewater discharges from industrial facilities.

关键词： Antennas   Satellite communications   5G mobile communication   Patch antennas   Metasurfaces   Loading   Loaded antennas   Satellite antennas   Substrates   Microwave antennas   5G   circular polarization   dual-linear polarization   metasurface   patch antenna   satellite communication   triple-band   UHF-RFID  

摘要： A triple-band, coaxial-fed, slotted microstrip patch antenna with metasurface loading is presented in this article. The first frequency band covers the 865-868MHz European UHF-RFID band, the second frequency band partially covers the 3300-4200MHz n77 and 3300-3800MHz n78 5G communication bands. Finally, the third frequency band partially covers the 3.7-4.2GHz satellite communication band. The S 11 <=-10 dB regions of the antenna-metasurface system lie between 833-885MHz, 3400-3550MHz and 4059-4164MHz. The system exhibits right circular polarization within the first and third frequency bands with a 3dB axial ratio bandwidth of 41MHz (5%) within the first band and 111MHz (2.7%) within the third band. The 3dB axial ratio beamwidth is +/- 60(0 )within the RFID band and +/- 30(0) within the satellite communication band. Moreover, the system also exhibits a dual-linear polarization within the second band. The radiation efficiency remains within the 75-85% region for all the three bands. The dimensions of the system are 0.28 lambda(0) x 0.28 lambda(0) x 0.023 lambda(0) at 865MHz. The proposed antenna-metasurface system is therefore very versatile, finding use as an UHF-RFID reader as well as for 5G and satellite communication.