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关键词： 射频识别   阅读器天线   耦合馈电   高增益   圆极化  

摘要： 提出一种圆极化高增益超高频射频识别(RFID)阅读器天线.天线为微带结构,由分别印制在上下两层介质基板上的辐射贴片、L形馈电结构、接地面、4个短路加载小贴片等组成.采用在辐射贴片中心蚀刻十字形槽,L形结构耦合馈电,在天线四角加载短路小贴片等方法,实现天线的圆极化和高增益.天线总尺寸(L×W×H)为160 mm×160 mm×21.6 mm,实测S_(11)≤-10 dB的频率覆盖范围为896~993 MHz,轴比小于3 dB的频率覆盖范围为902~940 MHz,覆盖频段内最大增益8.5 dBi.所设计的天线易加工、成本低、圆极化、增益高,可应用于各种RFID系统的测试环境中.

关键词： SHM   RFID   strain sensing   wireless sensing   passive sensing  

摘要： Strain-based condition evaluation has garnered as a crucial method for the structural health monitoring (SHM) of large-scale engineering structures. The use of traditional wired strain sensors becomes tedious and time-consuming due to their complex wiring operation, more workload, and instrumentation cost to collect sufficient data for condition state evaluation, especially for large-scale engineering structures. The advent of wireless and passive RFID technologies with high efficiency and inexpensive hardware equipment has brought a new era of next-generation intelligent strain monitoring systems for engineering structures. Thus, this study systematically summarizes the recent research progress of cutting-edge RFID strain sensing technologies. Firstly, this study introduces the importance of structural health monitoring and strain sensing. Then, RFID technology is demonstrated including RFID technology's basic working principle and system component composition. Further, the design and application of various kinds of RFID strain sensors in SHM are presented including passive RFID strain sensing technology, active RFID strain sensing technology, semi-passive RFID strain sensing technology, Ultra High-frequency RFID strain sensing technology, chipless RFID strain sensing technology, and wireless strain sensing based on multi-sensory RFID system, etc., expounding their advantages, disadvantages, and application status. To the authors' knowledge, the study initially provides a systematic comprehensive review of a suite of RFID strain sensing technology that has been developed in recent years within the context of structural health monitoring.

关键词： automated data collection   biologging   cognitive experiments   great tits   puzzle box   RFID   selective feeder   two-option device  

摘要： Advances in biologging technologies have significantly improved our ability to track individual animals' behaviour in their natural environment. Beyond observations, automation of data collection has revolutionized cognitive experiments in the wild. For example, radio-frequency identification (RFID) antennae embedded in 'puzzle box' devices have allowed for large-scale cognitive experiments where individuals tagged with passive integrated transponder (PIT) tags interact with puzzle boxes to gain a food reward, with devices logging both the identity and solving action of visitors. Here, we extended the scope of wild cognitive experiments by developing a fully automated selective two-option foraging device to specifically control which actions lead to a food reward and which remain unrewarded. Selective devices were based on a sliding-door foraging puzzle, and built using commercially available low-cost electronics. We tested it on two free-ranging PIT-tagged subpopulations of great tits Parus major as a proof of concept. We conducted a diffusion experiment where birds learned from trained demonstrators to get a food reward by sliding the door either to the left or right. We then restricted access of knowledgeable birds to their less preferred side and calculated the latency until birds produced solutions as a measure of behavioural flexibility. A total of 22 of 23 knowledgeable birds produced at least one solution on their less preferred side after being restricted, with higher-frequency solvers being faster at doing so. In addition, 18 of the 23 birds reached their solving rate from prior to the restriction on their less preferred side, with birds with stronger prior side preference taking longer to do so. We therefore introduce and successfully test a new selective two-option puzzle box, providing detailed instructions and freely available software that allows reproducibility. It extends the functionality of existing systems by allowing fine-scale manipulations of

关键词： antenna   folded dipole   T-match   transponder   UHF-RFID  

摘要： This paper presents a methodical design and prototyping of a passive European ultra-high frequency (UHF) band radio frequency identification (RFID) transponder. The transponder has a 70 x 17 x 0.3 mm(3) copper antenna whose design is based on the folded dipole architecture and utilizes techniques such as meandering and end loading to match a Texas Instruments (TI) UHF-RFID chip through a T-match feeding network. The tag's simulated and measured performances indicate good coverage of the entire UHF band with a return loss better than 10 dB. The transponder was then fabricated using inexpensive off-the-shelf materials and its performance was tested. The proposed tag achieved good gain, read range, and cost efficiency when compared with current folded dipole antennas and can be easily adapted for various applications such as supply chain, access or security, and vehicle identification.

关键词： Chipless RFID   radar cross section (RCS)   Read range   Array   Backscattering  

摘要： This paper presents three array configurations of chipless RFID tags for read range enhancement. A chipless RFID tag with eleven nested octagonal-shaped resonators is proposed. The proposed single element tag can encode 10 bits and has a read range of 1.20 m with a spectral efficiency of 1.821 bits/GHz and spatial efficiency of 2.066 bits/cm2. For further improvement of the tag read range, array configuration is utilized. A read range of 2.20 m, 3.20 m, and 4.20 m is achieved by 2x2, 3x3, and 4x4 array. The proposed chipless RFID tag is designed on an ultrathin substrate (0.15 mm) that provides conformability to the tag. A good agreement between the simulated and measured results is obtained.

关键词： electronic vehicle identification   UHF RFID   multiple RF characteristics   trajectory tracking  

摘要： Intelligent transportation systems (ITS) urgently need to realize vehicle identification, dynamic monitoring, and traffic flow monitoring under high-speed motion conditions. Vehicle tracking based on radio frequency identification (RFID) and electronic vehicle identification (EVI) can obtain continuous observation data for a long period of time, and the acquisition accuracy is relatively high, which is conducive to the discovery of rules. The data can provide key information for urban traffic decision-making research. In this paper, an RFID tag motion trajectory tracking method based on RF multiple features for ITS is proposed to analyze the movement trajectory of vehicles at important checkpoints. The method analyzes the accurate relationship between the RSSI, phase differences, and driving distances of the tag. It utilizes the information weight method to obtain the weights of multiple RF characteristics at different distances. Then, it calculates the center point of the common area where the vehicle may move under multi-antenna conditions, confirming the actual position of the vehicle. The experimental results show that the average positioning error of moving RFID tags based on dual-frequency signal phase differences and RSSI is less than 17 cm. This method can provide real-time, high-precision vehicle positioning and trajectory tracking solutions for ITS application scenarios such as parking guidance, unmanned vehicle route monitoring, and vehicle lane change detection.

关键词： Authentication   Elliptic curve cryptography   Radio frequency identification   RFID   Real-or-random (ROR) model  

摘要： The ever-increasing internet usage has led to creation of Internet of Things. RFID is one of the most common tracking tools for objects in Internet of Things, which has many different usages in navigation, medicine, military, smart cities, and smart homes. Therefore, researchers have presented various schemes to provide security of RFID systems. Based on our study results, most of proposed schemes have some weaknesses, such as vulnerability to some security attacks. Moreover, any proposed scheme should consider limitation of IoT systems in storage and power. This paper presents a secure and efficient protocol using elliptic curve cryptography for authentication and key agreement between RFID tag and reader. We evaluated security of our proposed scheme (HAKECC) by the Scyther tool, ROR model and BAN logic. The results show high security of HAKECC against different attacks. Later on, HAKECC was compared to other similar schemes based on communication cost (bits) and computation cost (ms);which shows considerably better performance compared to other similar schemes.

关键词： Fabric substrate   radio frequency identification tag   screen-printed antenna   flip-chip bonding parameter   performance  

摘要： The substrate material plays an important role in industrialized flip-chip technology of the passive ultra-high frequency radio frequency identification with antenna printed on flexible film. This work presents the flip-chip fabrication and performance evaluation of ultra-high frequency radio frequency identification with screen-printed antenna on common woven fabrics. The antennas were manufactured by screen printing a stretchable silver-based conductor directly on a common woven nylon fabric. The electrical and mechanical connection between the screen-printed antennas and microchips was formed by flip-chip technology, which bridged the antenna with the microchip under a heating contactor with additive anisotropic conductive adhesives, and the effects of heating contactor parameters (contactor pressure, temperature and duration time) on the performance of radio frequency identification tag prototypes were investigated, and the influence mechanism was discussed in terms of the conductivity, the resonance frequency shift and the morphology. The experiment results show that the flip-chip bonding conditions set in the case of screen-printed antenna on nylon fabric is 0.7 N contactor pressure, 120 degrees C heating temperature and 0.6 s heating duration time, different from the case of previous plastic-like thin film substrate, and this is mainly attributed to the compressive and rough surface of the fabric-based antennas. In addition, the flip-chip heating temperature should be consistent with that of screen-printed conductive ink to ensure a stable electrical connection between the antenna and microchip, as well as good performance of fabric-based ultra-high frequency radio frequency identification tags. These conclusions provide a tool for manufacturing large-scale fabric-based ultra-high frequency radio frequency identification tags and characterizing the process quality.

关键词： RFID   Pigs   Feeding behavior   Drinking behavior   Health monitoring  

摘要： Feeding and drinking behavior of individual growing-finishing pigs can be used for health and welfare monitoring by real time warning systems. The objective of this study was to develop and test a model detecting deviating feeding and drinking behavior of individual growing-finishing pigs based on Radio-Frequency Identification (RFID) registrations. Feeding and drinking behavior of growing-finishing pigs was recorded through low frequency RFID readings via ear tags. In three 16-week batches, twelve pens containing each twelve pigs were equipped with one drinker and two feeders. Four readers (each with eight antennas) recorded feeding and drinking activity of each individual pig in the pens. All tag readings were combined into visits, and subsequently visits into meals. The analyzed variables were number of meals per day, average interval between meals and maximum interval between meals per day for both feeding and drinking. A correlated-variables model with a Kalman filter was developed, generating alerts when the daily level was deviating from the expected level. For illustration of model results, the model was validated with culling recordings, which included all pigs that died or were euthanized during the experiment. Most cases of culled pigs corresponded with alerts given by the model, but sensitivity was hard to determine due to low number of cases and specific circumstances of the culled pigs. The specificity of the model was similar for feeding and drinking behavior, and was highest for number of meals (93-99%), followed by the average interval between meals (90-96%) and the maximum interval between meals (86-97%), depending on desired confidence interval. The developed model is promising for early detection of health problems in growing-finishing pigs, but further validation should occur on a bigger scale in order to increase accuracy of results and improve knowledge required for practical implication of the model.

关键词： vehicular networks   RFID   tag identification   capture effect  

摘要： Passive radio-frequency identification (RFID) systems have been widely applied in different fields, including vehicle access control, industrial production, and logistics tracking, due to their ability to improve work quality and management efficiency at a low cost. However, in an intersection situation where tags are densely distributed with vehicle gathering, the wireless channel becomes extremely complex, and the readers on the roadside may only decode the information from the strongest tag due to the capture effect, resulting in tag misses and considerably reducing the performance of tag identification. Therefore, it is crucial to design an efficient and reliable tag-identification algorithm in order to obtain information from vehicle and cargo tags under adverse traffic conditions, ensuring the successful application of RFID technology. In this paper, we first establish a Nakagami-m distributed channel capture model for RFID systems and provide an expression for the capture probability, where each channel is modeled as any relevant Nakagami-m distribution. Secondly, an advanced capture-aware tag-estimation scheme is proposed. Finally, extensive Monte Carlo simulations show that the proposed algorithm has strong adaptability to circumstances for capturing under-fading channels and outperforms the existing algorithms in terms of complexity and reliability of tag identification.