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关键词： Location awareness   Dipole antennas   Reflector antennas   RFID tags   Impedance   Antenna measurements   Visualization   Localization   radio frequency identification (RFID)   received signal strength indicator   UHF antennas  

摘要： In this study, a low-cost dual-chip RFID tag antenna is proposed for indoor localization. The antenna integrates two RFID chips, each generating opposing radiation patterns. Angle-of-arrival based localization is performed with a single reader by analyzing the Received Signal Strength Indicator (RSSI) and the RSSI ratio of both chips. The antenna incorporates a mechanically adjustable reflector at the back that allows simple beam elevation control to tune the antenna for different indoor environments. The proposed dual-chip tag was measured in an indoor environment with different beam configurations. The localization is performed using a simple sinusoidal regression model with three model parameters and a linear regression model with two model parameters to fit the RSSI ratio of both chips and the RSSI of each individual chip, respectively. The proposed technique yields an average angle-of-arrival error better than 6.6 degrees within the tag's horizontal detection range of 4.2 meters.

关键词： leaf moisture content (LMC)   forestry Internet of Things (FIoT)   radio frequency identification (RFID)   hyperdimensional computing (HDC)   non-destructive detection  

摘要： Leaf moisture content (LMC) directly affects the life activities of plants and becomes a key factor to evaluate the growth status of plants. To explore a low-cost, real-time, rapid, and accurate method for LMC detection, this paper employs Ultra-High-Frequency Radio-Frequency Identification (UHF RFID) sensor technology. By reading the tag information attached to the back of leaves, the parameters of the RSSI, phase, and reading distance of the tags are collected. In this paper, we propose an enhanced Multi-Feature Fusion algorithm based on Hyperdimensional Computing (HDC) called MFFHDC. In our proposed method, the real-valued features are encoded into hypervectors and then combined with Multi-Linear Discriminant Analysis (MLDA) for the feature fusion of different features. Finally, a retraining method based on Cosine Annealing with Warm Restarts (CAWR) is proposed to improve the model and further enhance its accuracy. Tests conducted in the experimental forest show that the proposed mechanism can effectively predict the LMC. The model's Mean Absolute Error (MAE), Root Mean Square Error (RMSE), and Coefficient of Determination (R2) reached 0.0195, 0.0255, and 0.9131, respectively. Additionally, comparisons with other methods demonstrate that the presented system performs excellently in most aspects. As a lightweight model, this study shows great practical application value, particularly for the limited data volume and low hardware costs.

关键词： metrology   calibration   digitalization of metrology   digital calibration certificate   RFID  

摘要： The digital transformation of metrology is one of the most active activities in the field of metrology at present, where the digital calibration certificate (DCC) being developed is the topic receiving the most concern in the current digital transformation. In practical industrial applications, the issue of storage carrier for the DCC plays a crucial role in its promotion and implementation. To address this issue, a DCC meta-model called DCC-Lite schema has been designed along with a corresponding processing method. This solution involves compressing and segmenting the DCC to make it suitable for storage using RFID tags. These RFID tags are affixed to the instruments and accompany them throughout their usage. Additionally, the DCC-RFID processing system has been developed to validate the effectiveness of the DCC meta-model and its corresponding processing method within a wireless temperature acquisition system. Experimental results demonstrate that the system successfully reads and writes the DCC stored within the RFID tag group. Furthermore, it enables automated parsing of the DCC calibration data by the machine and real-time compensation of measurement data to reduce measurement errors.

关键词： UHF RFID   Circularly-polarized characteristic   Impedance bandwidth   Axial ratio   ThingMagic M6E   App Inventor 2  

摘要： In response to the rising demand for adaptable and versatile RFID reader antenna, this paper presents an integrated reader system featuring an array of four antennas. The primary objective is to design four identical, circularly polarized, high-gain, wide-band antennas that cover the 860-960 MHz UHF RFID band. Each antenna consists of three layers, the radiator and director layers, designed as patch antennas with trimmed edges and a central slot, while the reflector layer is constructed from a copper material. These layers are assembled with four Teflon spacers, and a coaxial connector is utilized for feeding the antenna. An open-circuit stub is used to improve impedance matching. CST Microwave Studio was employed for design optimization. The four sector antennas achieve a 150 MHz bandwidth (833-983 MHz) and a maximum gain of 8.4 dBi. When combined with a four-port RFID reader (ThingMagic M6E), the antenna system generates four electronically switchable beams in the azimuth plane. The proposed antenna exhibits lefthand circular polarization (LHCP) within the RFID ISM band, maintaining an axial ratio (AR) between 1 dB and 3 dB. The antenna array, including the reader and control unit, measures 255 x 255 x 210 mm. Simulation and measurement results confirm the system's performance and functionality.

关键词： MIMO communication   wireless communications  

摘要： In this letter, a novel integrated sensing and communication (ISAC) scenario with wireless power transfer (ISAC-WPT) is investigated. In this new setup, an access point simultaneously employs communication and sensing beams to serve a communication user, detect an RFID tag, and power an energy receiver. The objective is to design the sensing and communication beams to minimize the total transmit power while satisfying the requirements of tag detection, communication, and energy harvesting. To address the corresponding non-convex problem, the constraints are reformulated into convex second-order cone constraints, thereby obtaining the globally optimal solution. To further reduce computational complexity, zero-forcing is employed to design the beamforming vectors, followed by solving a convex optimization problem to determine the optimal power allocation between sensing and communication beams. The simulation results demonstrate the effectiveness of the proposed beamforming designs, highlighting the potential of ISAC-WPT Backscatter RFID systems. A novel integrated sensing and communication (ISAC) scenario with wireless power transfer (ISAC-WPT) is investigated, consisting of an AP, a passive RFID tag, a communication user, and an energy receiver. Two schemes are proposed to design the sensing and communication beams to minimize the total transmit power while satisfying the requirements of tag detection, communication, and energy harvesting, and the effectiveness of our proposed beamforming designs is verified by simulations. The proposed methods can enhance the functionality and performance of ISAC-WPT backscatter RFID systems. image

关键词： IoT   safety   RFID   school bus   transportation  

摘要： School districts globally implement comprehensive and expensive strategies to offer safe bus transportation to and from school. However, these technologies are unfeasible to schools with limited financial resources, thereby leaving students at risk of serious injury. This study focuses on five major obstacles to safe school transportation: 1) forgetting students on the bus unattended;2) students' abnormal behavior;3) overcrowding;4) abnormal driver behavior;and 5) the risk of a bus running over children after they have disembarked. This paper developed an intelligent system using the Internet of Things, including rule- based and mathematical solutions to overcome the five transportation safety issues in student buses mentioned above, and to enhance student safety, using a bracelet system, short- and longRFID sensors, and a processing unit to monitor the bus and its surrounding area. Therefore, in this paper, the proposed solution is superior to previous works in the same field. It is distinguished by its comprehensiveness and reasonable cost, making it affordable and easy to both install and maintain.

关键词： UHF RFID tag-based sensors   Non-destructive testing (NDT)   Structural health monitoring (SHM)   Internet of things (IoTs)   Commercial off-the-shelf (COTS) flexible tag   3D antenna  

摘要： The application of the UHF RFID technique in non-destructive testing (NDT) and structural health monitoring (SHM) has gained increasing attention due to its wireless, battery-less, and cost-effective attributes. It offers a promising approach for SHM and the Internet of Things (IoTs). This paper reports commercial off-the-shelf (COTS) flexible UHF RFID tag-based sensors for corrosion characterization on coated mild steel. Two types of COTS flexible UHF RFID tags with different bends are fabricated as sensors. The received signal strength indicator (RSSI) measurement is implemented to characterize the corrosion. Three parts (T-match area, dipole arms, and dipole loadings) of the two tags are tested for sensing purposes, and comparison and discussion of sensitivity, read range, and results are provided. This study successfully validates the feasibility of the proposed tag-bent method for corrosion characterization undercoating. It can be concluded that the dipole arm part of the applied COTS tags is the most sensitive area.

摘要： Artificial intelligence plays an important role in medical management, but there is a problem of poor wireless communication effect. In the process of management data transmission, it is easy to distort, high loss rate, limited transmission dependence and other problems. Therefore, this paper integrates RFID technology into medical management and analyzes the transmission effect. First of all, RFID technology is used to standardize the transmission data in medical management, divide it according to departments, categories, and personnel, and screen out the information data that meets the requirements. Then RFID technology mixes RFID on the transmitted data and compares it with wired transmission to verify the rationality and accuracy of the transmitted data and the satisfaction of medical staff. MATLAB simulation shows that under the conditions of transmission standards and IEEE protocols, RFID technology has better data transmission effects, higher accuracy and rationality, and better satisfaction rates, giving full play to the advantages of wired and RFID.

摘要： This research work bring in a simple circularly polarized slot antenna with Proximity Couple Feed for the utilization in Ultra high frequency (UHF) band Radio-frequency identification (RFID) reader devices. The presented antenna is fed using proximity couple technique with a bent like feeding structure to achieve improved impedance matching and meandering slot etched on ground plane to achieve circular polarization in targeted frequency band. The results obtained from investigation exhibit that the introduced antenna shows a very good return loss (RL)-10-dB bandwidth (BW) 110MHz (865-975) MHz / 12.1% and below 3-decible axial ratio (AR) BW 92(862-954) MHz/ 10.5%. In addition the designed antenna shows maximum gain of 5.89dBic in the targeted frequency band. The proposed slot antenna shows improved results and it has a simple geometry, small in size (120x80x0.8 mm3) which makes it suitable for the use in UHF (860-960MHz) RFID reader applications.

摘要： The data on Radio Frequency Identification (RFID) tags is not encrypted, which makes it feasible for others to access it, despite the fact that RFID is a widely used technology. One cryptographic approach utilized for securing data on RFID tags is key encryption. It is now possible to write and read encrypted data on RFID tags with more security and accuracy than before, according to experiments. With the help of primitive feedback polynomials, six linear feedback shift registers (LFSR) of varying lengths are combined in this work for creating a lightweight stream cipher. The resulting random sequence is fed into the S-Box, a component of the Data Encryption Standard (DES), which hides the relation between the plaintext, cipher text, and key. Also used tRNA a bioinformatics system (tRNA) to generate new S-Box by using standard amino acid to obtained confusion for our cryptosystem. The generated sequence represents the key stream that can be used to encrypt the data stored on RFID tags. The proposed approach was analyzed by using statistical tests and show a good result, it passes 11 of 14 proximity test.