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关键词： Space applications  

摘要： This paper presents an ultra-high frequency (UHF) RFID tag antenna designed to operate within the American frequency band (902-928 MHz) and perform reliably when placed on metallic objects. The design features a microstrip dipole antenna with symmetrical U-shaped stubs, capacitively coupled to a metallic patch and grounded with a substrate. The antenna is printed on a low-cost FR4 substrate (1.6 mm thickness), with overall dimensions of 90 mm × 95 mm × 1.6 mm. The antenna achieves a realized gain of-4.8 dB, with a free-space reading range of approximately 7 m, which increases to 10.5 m when placed on a 50 cm× 30 cm metallic plate. The key of this design lies in its use of capacitive coupling, which eliminates the need for metallic vias or shorting walls. This simplification not only facilitates mass production but also enhances the design’s performance, offering a superior reading range on larger metallic objects compared to other designs reported in the literature that provide a small reading range. The proposed antenna offers a robust solution for RFID applications on both metallic and non-metallic objects. © 2025, Advanced Electromagnetics. All rights reserved.

关键词： Liquids   Permittivity   Sensor phenomena and characterization   Table lookup   Transmission line measurements   Radiofrequency identification   Dielectrics   Antennas   Permittivity measurement   Substrates   Antenna-based sensors (ABSs)   dielectric characterization   liquids   radio frequency identification (RFID) sensors  

摘要： Remote characterization of liquids can be beneficial in various industry sectors such as food and oil industries, medical diagnostics, agriculture, or waste management. However, current wireless solutions are often expensive and labor-intensive. Antenna-based sensors (ABSs) can potentially decrease the complexity and cost of current solutions. Ultrahigh-frequency (UHF) radio frequency identification (RFID) sensors for liquid characterization have the potential to provide remote monitoring while fulfilling the previous requirements. This work demonstrates the combined effects of the dielectric properties on the operation of RFID-based sensors and it presents an innovative approach for estimating the dielectric properties of a liquid under test (LUT) from the read range peak frequency and magnitude variations of a UHF RFID tag. The tag antenna consists of a patch-like antenna with an absorbent embedded into its substrate. Filling the absorbent with different LUTs modifies the dielectric properties of the substrate which has a measurable effect on the tag read range. Measurements show that the proposed method together with the specific sensor design enables the dielectric characterization of liquids using an energy-efficient and low-cost solution achieving an accuracy over 93.5% and 84% in the estimation of the LUT relative permittivity and the loss tangent, respectively, compared to the transmission line (TL) method.

关键词： Liquids   Interference   Sensors   RF signals   Feature extraction   Accuracy   Attenuation   Radar tracking   Target tracking   Radio frequency   Convolutional neural network based on a hybrid attention mechanism (CNNam)   multipath suppression   phase and received signal strength indication (RSSI)   white wine concentration recognition  

摘要： It is essential to accurately detect liquid concentration in the production processes. Radio frequency identification (RFID) is commonly used for item identification and detection due to its sensing capabilities. This article introduces the radio frequency-two-stage weighted multipath suppression convolutional neural network based on a hybrid attention mechanism (RF-TMS-CNNam) system, a novel approach that combines RFID technology and deep learning models to accurately determine the concentration levels of various liquids. The propagation of radio frequency (RF) signals through the target liquid is influenced by concentration levels, resulting in distinct changes in both phase and received signal strength indication (RSSI). These changes in phase and RSSI are utilized as features to detect the target. Subsequently, the features are extracted and fed into the convolutional neural network (CNN) to train a model for classifying different liquid concentrations. The problem of multipath interference is common in RFID sensing, distorting the sensing phase and RSSI and affecting the accuracy of target sensing. This article proposes a two-stage weighted multipath suppression (TMS) method to tackle this issue. In the first stage, the process identifies the channel with the least multipath interference. In the second stage, it assigns different weights to signals detected by various channels and tags. This approach significantly enhances the power of the direct path signal while reducing the power of multipath interference to an average value due to its randomness. After suppressing the multipath interference, "clean" features are extracted to train the liquid concentration detection model. Experiments were conducted to evaluate the performance of the proposed system. The experimental results show that the RF-TMS-CNNam system achieves an average accuracy of 97.8% and 96.8% in detecting the concentration levels of both white wine and wine. The proposed method also enables non-

关键词： integrated sensing and backscatter communication (ISABC)   beamforming design   convex optimization  

摘要： In this paper, we propose a novel MIMO-enabled integrated sensing and backscatter communication (MIMO-ISABC) system to serve multiple users, and focus on the transmit beamforming design for the system. Under the total transmit power constraint, we aim to design sensing and communication beams that meet both tag detection and communication requirements. First, we use minimum mean square error (MMSE) beamforming to design the beamforming vectors, followed by convex optimization to allocate power between sensing and communication. Then, we investigate a joint beamforming optimization problem to minimize the total transmit power while meeting the tag detection and communication requirements. To solve this, we transform the non-convex constraints into convex second-order cone constraints. The experimental results demonstrate the validity and performance of the proposed scheme and associated algorithms. The proposed MIMO-ISABC system offers great potential for applications in IoT scenarios.

关键词： metallic platform   parasite strips   RFID Tag   tapered patch   UHF   wideband  

摘要： A long-range, compact, wideband Ultra High Frequency (UHF) radio frequency identification (RFID) tag is proposed. The design features a triangular patch, designed to achieve wideband impedance matching. The tag exhibit -10 dB bandwidth from 753 to 917 MHz with a substrate thickness of 1.575 mm. The overall size of the tag is 121 x 30 x 1.575 mm3. The gain and bandwidth for varying substrate thickness is investigated. Further, two parasitic strips are designed alongside the patch to operate the tag more effectively at Federal Communications Commission (FCC) band in simultaneous with European Telecommunications Standards Institute (ETSI) band with increased read range. With parasitic strips, the tag exhibits -10 dB bandwidth from 766.5 to 896.5 MHz and 905 to 943.6 MHz which covers the bandwidth requirements in Europe, Asia, and North America. A prototype of the proposed tag is fabricated and experimentally tested with the RFID Higgs 4 IC. The tag provides a read range of over 14 m in 865-870 MHz and 13 m in 902-928 MHz when the tag is operated in free space and a read range of over 10.2 m in 865-870 MHz range and 10.3 m in 902-928 MHz range when mounted on a metallic surface of size of 200 x 200 m2 . The performance parameters of the designed tag are also compared with some commercially available designs.

关键词： array antenna   expandable   fractal structures   large area   near field   ultra-high-frequency (UHF) radio frequency identification (RFID)  

摘要： In this paper, a large, compact array antenna that can be expanded in the 2-D plane is proposed for near-field radio frequency identification applications. By the introduction of the fractal structure and corner joint method, the array is easy to expand in the 2-D plane. An antenna element can be divided into a dozen or so loops, and traveling wave distribution makes sure that every loop is excited in a time period. So that a strong and uniform magnetic field could be generated in a large area. As a proof of concept, array antennas with $1 \times 8$, $2 \times 4$, and $3 \times 3$ elements are designed, fabricated, and measured. The measured bandwidth of the antennas covers the entire Chinese standard. Reading distances of the proposed large array antennas achieved up to 57 mm. Results show that the proposed antenna could realize flexibility and extendibility in a large area with stable and uniform magnetic field distribution.

摘要： This project endeavors to develop a remote start system for Automated Guided Vehicles (AGVs) utilizing RFID technology, aimed at augmenting operational oversight. The system will facilitate remote initiation and monitoring of AGV functions, thereby enhancing operational flexibility and efficiency. The study will offer a comprehensive examination of the system’s design, functionality, and efficacy, encompassing component descriptions, design intricacies, encountered challenges, and a thorough evaluation of its speed, precision, and operational efficiency. By integrating RFID technology with AGVs, this research contributes to advancing the capabilities of automated material handling systems, with implications for enhancing productivity and responsiveness in diverse industrial settings.

关键词： RFID   Anti-counterfeiting   CRC   PHY identification   Tag  

摘要： In the realm of radio frequency identification (RFID) systems, combatting counterfeit tags through anti-counterfeiting technologies has garnered significant attention, particularly physical layer identification methods, lauded for their cost-effectiveness and simplicity in deployment. Nonetheless, the performance of physical layer recognition method is significantly impacted by the conditions of the tag detection setting, especially in scenarios characterized by low signal-to-noise ratio (SNR), where classification accuracy tends to suffer. To tackle this challenge head-on, this study proposes the implementation of a cognitive risk control strategy, which fine-tunes tag distance within the tag classification process to bolster the SNR and enhance recognition precision. Beyond the enactment of cognitive risk control, this paper extends its focus to encompass enriched time domain and frequency domain feature extraction, totaling 104 features, aimed at further enhancing classification efficacy. Leveraging software-defined radio devices, classification experiments encompassing seven popular tag types from three distinct manufacturers were conducted. Results from these experiments reveal that upon integrating the cognitive risk control strategy, the average accuracy of tag classification experiences an approximate 11% increase. Concurrently, in comparison to traditional twenty-eight and seven features, the adoption of one-hundred-and-four features translates to an enhancement in classification accuracy by roughly 4.3% and 5.3%, respectively. These findings not only underscore the efficacy of cognitive risk control in elevating label classification accuracy within low SNR environments but also underscore the potential for augmenting classification performance through an increased feature set.

关键词： 高职教育   工作过程   教学改革   射频识别  

摘要： 以“射频识别技术与应用”课程为实证案例,系统阐述包含目标设定、情景构建、实践项目设计以及创新思维培养在内的全面改革方案,深入探究高等职业教育中基于工作过程的教学项目改革。通过前期筹备、理论传授、实践操作与成果展示等环节的精细实施,改革成效显著,教学质量得到提升,学生的职业技能与创新创业能力得到增强。为高职教育中该类教学改革的推广与实施提供了有力支撑,有助于培育更多高素质技术技能人才。

关键词： RFID   人工智能   智能冰箱   食材管理   远程监控  

摘要： 在该人工智能冰箱系统中,核心控制单元采用STM32F103RCT6微控制器,负责协调各模块的工作和数据处理。食材识别功能通过RFID读写模块实现,该模块能够读取食材上附着的RFID标签信息,从而识别食材种类。为了监测和控制冰箱内的环境条件,系统采用了DHT11温湿度传感器来实时获取温度和湿度数据。制冷功能由半导体制冷片承担,根据控制系统的指令调节冰箱内的温度。为了实现用户友好的交互界面,系统配备了HMI串口触摸屏,用于显示信息和接收用户输入。远程控制和监控功能则通过ESP8266物联网模块实现,允许用户通过智能手机或其他设备远程管理冰箱设置和监控食材状态。整个系统的设计旨在提供一个高度自动化和用户友好的智能冰箱解决方案,以提升家庭食材管理的效率和便捷性。