教学课程资源库 更多>>

关键词： 超高频RFID   灵敏度测量   自动调谐   阻抗匹配   共轭匹配  

摘要： 灵敏度是衡量无源UHF RFID芯片性能的关键指标,传统测量通常需要匹配网络或专用天线,方法复杂且易受阻抗失配影响。本文提出一种基于自动调谐的芯片灵敏度测试方法:利用自动阻抗调谐技术在测量过程中动态调整系统输出阻抗,使芯片获得最大可用功率,无需专门设计匹配网络。其中,UHF RFID芯片灵敏度的实验测试是采用矢量网络分析仪(VNA)、自动调谐器、Voyantic Tagformance Pro测试仪等搭建测试平台,样品选取了某主流UHF芯片。该芯片的测试结果发现,在915 MHz下的激活功率约为-14.7dBm,与厂商标称的单端口写入灵敏度(-14.6dBm)相差不超过0.1dB,已在测量不确定度范围内。应该看到,相比手动匹配方法,本测试方案显著提高了测量效率与准确度,并具备良好的可重复性和可扩展性。

关键词： 射频识别   物联网   有源标签   标签盘点   防碰撞算法   盘点准确率  

摘要： 在读写器盘点符合GB/T 28925标准的有源RFID标签过程中,标签使用8位随机数RN8作为一次盘点循环中的唯一标识。然而,当标签数量较多时,产生相同RN8的概率显著增加,不利于读写器实现大量标签的准确盘点。针对该问题,提出了一种能够准确盘点大量有源RFID标签的方法,该方法通过让标签在盘点过程中广播自身RN8和在盘点结束后广播自身收集时隙号Nr,保证盘点过程中RN8和Nr的唯一性,实现读写器对标签的单一化处理和准确盘点。实验结果表明,与改进前的盘点方法相比,该方法可以将盘点准确率提升至99.9%。

关键词： Advanced material   chipless radio frequency identification (CRFID)   greenhouse test box (GTB)   moisture test box (MTB)   multiparameter sensing   performance network analyzer (PNA)   Advanced material   chipless radio frequency identification (CRFID)   greenhouse test box (GTB)   moisture test box (MTB)   multiparameter sensing   performance network analyzer (PNA)  

摘要： This article investigates a low-cost FR4-based 8-bit chipless radio frequency identification (CRFID) tag sensor with a multifunctional sensing application and the operating frequency range for the proposed sensor varies from 800 MHz to 5 GHz. The tag's design is based on a complimentary C-shaped resonator with dimensions 50 x 50 x 0.75 mm(3). A material-based sensing method has been adopted to sense the multiple environmental parameters. Advanced materials such as Kapton HN and graphene are embedded between the gaps of the copper slot and used as dedicated moisture and temperature sensing. The Kapton and graphene were tested through Fourier transform infrared spectroscopy (FTIR) spectroscopy to determine its absorption rate. The method of excitation for the proposed sensor is linear-polarized plane wave excitation. Here, two standardized horn antennas have been used for plane wave excitation. This research work proposes two specific sensor performance measurement setups to sense the environmental parameters: the moisture test box (MTB) and the greenhouse test box (GTB). The sensing is achieved by a maximum frequency shift of 300 MHz. The amplitude, resonant frequency, and variance are three major parameters extracted from the moisture and temperature sensor as a function of frequency. Lorentz second-order polynomial equations are used to fit the nonlinear, frequency variant sensor response to an optimal value along with the variance analysis techniques to interpret the sensing data for extracting the features in the CRFID system. The reversible behavior of the tag sensor on the low-cost FR4 substrate concerning moisture and temperature sensing is a better substitute for the other commercial environmental sensors.

关键词： 射频识别   开口谐振环   谐振频率偏移量   无线应变测量   传感器阵列  

摘要： 现有无线无源应变传感器存在检测方向单一、灵敏度低、尺寸大等问题,难以满足复杂受力条件下飞机机翼等大型金属结构应变状态评估的需求。针对这一问题,利用开口谐振环高辐射能力、低损耗以及高品质因数等优点,基于三角函数与矢量分解原理设计了一种基于开口谐振环的小型化无线无源应变传感器阵列。该传感器阵列由3个夹角120°的传感器构成,通过提取各传感器谐振频率偏移量实现金属结构件上应变大小和方向的反演。通过ADS软件得到传感器的阻抗参数,以传感器谐振频率为优化目标采用HFSS软件完成了传感器结构小型化和阻抗匹配优化设计,并利用COMSOL软件进行“力-磁”耦合分析验证了传感器的应变检测性能,随后完成传感器制备。实验结果表明,传感器在电长度方向和电宽度方向的灵敏度分别为-1.517和-0.732 kHz/με,所提出的传感器阵列应变大小的检测精度在8.5%以内,应变方向检测误差在10°以内。该传感器阵列能够实现对金属结构表面应变大小和方向的检测,具有灵敏度高、尺寸小以及成本低等优点。

关键词： BIM   IOT   建筑运维   RFID   改进SSA  

摘要： 随着科学技术的快速发展,建筑信息模型和物联网技术在建筑运维管理得到广泛应用。针对目前建筑运维管理效率低和质量差的问题,提出了一种将建筑信息模型和射频识别技术相结合的建筑运维管理系统,并设计一种改良的麻雀搜索算法优化射频识别系统的网络配置。将改进麻雀搜索算法与其他算法进行对比分析,结果表明,该算法在三目标优化和四目标优化任务中,均优于对比算法。同时将提出的建筑运维管理系统进行应用效果对比分析,该系统均高于对比系统。研究设计的建筑运维管理系统在减少管理开支和提升管理效能方面表现显著,同时对增强建筑运维管理的质量起到了积极作用。

关键词： Potamodromous fish   Fishway   Ecological continuity   Migration   Telemetry  

摘要： Movements of potamodromous fish are poorly understood, especially in large rivers, because studies often focus on fishway evaluation and diadromous species. Here, we assessed the movements of 808 fish of five potamodromous species (Barbel, Barbus barbus;Common bream, Abramis brama;Nase, Chondrostoma nasus;Asp, Leuciscus aspius and chub Squalius cephalus) over 14 years in a highly anthropized river system, the Rhine River, where hydropower plants were progressively equipped with fishways including RFID antennas. The objectives of the study were 1) to characterize long-term and large-scale individual movement patterns of five potamodromous fish species 2) to assess inter- and intra-specific variations based on quantitative movement metrics and 3) to create a typology of individuals based on their movements. Results showed that, despite high intra-specific variability, the inter-specific differences were strong enough to highlight long-term and large-scale species- specific behaviors. Breams exhibited movements that occurred essentially during spawning migration period and at the reach scale. In contrast, barbels were more active, with more movements outside their spawning migration period, showed more large-scale and downstream movements, and used navigation locks more often than other species. For this species, the maximum distance between the two furthest recorded positions at the basin scale was exceptionally high (max = 155 km). We conclude that potamodromous species undoubtedly perform largescale movements, which are characterized by both species-specific and common features. Therefore, efforts need to be made to better consider their ecological needs and swimming capabilities when planning and designing effective fishways for the diverse range of species that move within river systems.

关键词： antifuses   carbon black   polyethylene glycol   RFID temperature indicators   Thermoresponsive materials  

摘要： Time-temperature indicators (TTIs) play an important role in logistics, supply chain, and inventory management. They indicate a visual signal when the temperature exceeds a predefined threshold. However, TTIs require a manual process of checking each label individually, making their applications time and cost-intensive. Radio frequency identification (RFID) tags can streamline the process with data readily available in digital format. Challenges of RFID-based temperature sensors are the need for a battery and incompatibility with standard readers. In this study, thermoresponsive composites are developed based on acetylene black (AB) and poly(ethylene glycol) (PEG). By mixing two PEG binders having different molecular weights, the resulting composites function as thermal antifuses, irreversibly transitioning from a high resistance (HR) state to a low resistance (LR) state. The optimal composition detects a threshold temperature of approximate to 60 degrees C and shows a large HR/LR ratio of >10(3). Combining the antifuse based on this unique AB/PEG composite with an RFID tag with a tamper detection capability allows the fabrication of a battery-free, passive RFID temperature indicator equipped with a 1-bit non-volatile memory. The device can track the environment of temperature-sensitive items, save the status, and indicate a digital output when a temperature threshold has been exceeded.

关键词： Blockchain   Bayesian theory   Radio frequency identification   Emergency material dispatch  

摘要： When an emergency occurs, it is very important to ensure the efficient and orderly dispatch of materials. It can make the progress of rescue work smooth, avoid material waste, and improve public satisfaction. However, it is difficult for the existing system to judge whether the received message is credible because material demanders may overstate requirements either intentionally or unintentionally. The paper establishes a credit value system for material dispatching based on blockchain technology. The system is of material demanders and utilizes the posteriori information in Bayesian theory to update the credit value. At the same time, radio frequency identification tags are used as the information transfer medium to improve the credibility and efficiency of the system. When establishing the credit value system with Bayesian theory, the paper use MATLAB to calculate and visualize the range of parameter values. Finally, the paper compare the efficiency and cost of the improved material dispatching system with the traditional system and verify the advantages of the model. The results of the analysis show that the improved system has the advantages of high speed, high privacy, distributed computing, high credibility and automatic information flow. It can be further generalized to other complex dispatching scenarios.

关键词： Authentication   Internet of Things   Object recognition   Gold   RFID tags   Performance evaluation   Feature extraction   Surface impedance   Impedance   Antennas   Device authentication   user authentication   RFID   deep learning  

摘要： User and device authentication are vital to the deployment of smart Internet of Things (IoT) devices. Unfortunately, achieving robust authentication on a diverse set of heterogeneous IoT devices remains an open problem. This article presents Scenario, a generic authentication method to support user-device authentication on a wide range of IoT devices, using RFID-based wireless sensing. Scenario only requires attaching an RFID tag on the target device surface. It then uses the unique RFID signal characteristics introduced by the device material and user gestures to perform device and user authentication. We developed a prototype of Scenario using commercial off-the-shelf devices and applied it to a multi-device smart environment. Experimental results show that Scenario is reliable, giving an average identification accuracy of 97.3% and 96.7% of the device and user authentication stages in diverse environments, respectively.

关键词： Temperature measurement   Humidity   Temperature sensors   Substrates   Semiconductor device measurement   Consumer electronics   Silver   Humidity measurement   Antenna measurements   Sensor applications   environmental sensor   printed electronics   radio-frequency identification (RFID)   sensor tag   sustainable   wireless   wireless  

摘要： The growing demand for sustainable and efficient environmental monitoring systems has driven the development of innovative sensor technologies. This study presents a hybrid ultra-high frequency radio-frequency identification (RFID) sensor tag fabricated on uncoated paper substrate, which constitutes approximately 87% of the tag's mass thereby making the sensor tag more sustainable and eco-friendly. The sensor tag integrates an AS3213C.4 RFID chip together with an antenna, an interdigitated capacitor as a humidity sensor, pads, and interconnects. Temperature sensing is facilitated by the RFID chip's internal temperature sensor, while humidity is monitored through changes in the printed capacitor. All structures except for the chip were screen printed using a conductive silver ink. The silver layer exhibited a thickness of 5.6 mu m and a sheet resistance of 56.4 m Omega/sq, sufficient for wireless communication over a distance of 2 m. The sensor was wirelessly interrogated using a Kathrein antenna and reader system, with data retrieved via commercial software. Temperature tests demonstrated accurate readings from 26 degrees C to 80 degrees C, aligning with the chip's specifications of -40 degrees C to 125 degrees C, with a precision of 1 degrees C in the range of 10 degrees C to 50 degrees C. Humidity measurements in a climate chamber, conducted between 15% and 55% relative humidity, showed an average sensitivity of 0.45% per % humidity change. Hysteresis effects of 7.4% were observed due to the moisture absorption and structural changes of the paper substrate. This work highlights the potential of paper-based sensor tags for sustainable environmental monitoring, aligning with the principles of Industry 4.0 and the Internet of Things (IoT), while addressing the growing challenge of electronic waste.