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关键词： graphene‐   assembled film (GAF)   near‐   field communication (NFC)   RFID   5G   wearable device  

摘要： Benefiting from the high conductivity and superb flexibility, graphene-based materials are promising to replace metal for near-field communication (NFC) applications. Herein, we report a flexible NFC tag antenna based on high-conductivity graphene-assembled films (HCGAFs) and investigate how the performance of the antenna is affected by antenna design and human body effect. The fabricated prototype via a one-step laser-direct mold engraving method shows a 10 dB bandwidth of 2.5 MHz centering at 13.70 MHz with a quality factor (Q) of 9.19. The maximum read range of the HCGAF NFC tag is measured to be around 7.5 cm, comparable to the commercially available metal NFC tags. Moreover, the flexible nature of HCGAFs guarantees excellent mechanical stability and deformation insensitivity, especially when compared to commercial metal-based counterparts. We further demonstrate the practical applications of the HCGAF tag as key card and electronic business card in the vicinity of human body.

关键词： Radiofrequency identification   Delays   Broadband antennas   Attenuation   Phase measurement   Frequency measurement   Field programmable gate arrays   Adaptive   broadband   carrier cancellation   radio frequency identification (RFID)  

摘要： Ultrahigh frequency radio frequency identification (UHF RFID) uses backscattered electromagnetic (EM) modulation techniques to communicate between readers and tags. The suppression of the carrier signal leaked from the transmission channel to the receiving channel is the key factor that determines the reader's sensitivity. In this letter, a broadband, fast carrier cancellation technique is proposed. The reader system uses two transmission ports: one is for the transmission of the interrogating signal and carrier waves (CWs) and the other port can dynamically sample the leakage signal in the receiving channel and generate a cancellation signal with the same amplitude but opposite phase of the leakage. This technique is implemented using an AD9361 transceiver chip as RF front end and a field-programmable gate array (FPGA) board as the protocol and cancellation controller. Experiments demonstrate that a suppression of around 92 to 106 dB can be achieved within 0.5 ms in a UHF RFID system. The cancellation technique is also broadband;with a matched antenna, the experiment shows that cancellation can work effectively from 0.3 to 6 GHz.

关键词： RFID   ultra-lightweight   authentication protocol   stream cipher  

摘要： In recent years, with the continuous development of the Internet of Things, radio frequency identification (RFID) technology has also been widely concerned. The computing power of low cost tags is limited because of their high hardware requirements. Symmetric encryption algorithms and asymmetric encryption algorithms, such as RSA, DES, AES, etc., cannot be suitable for low cost RFID protocols. Therefore, research on RFID security authentication protocols with low cost and high security has become a focus. Recently, an ultralightweight RFID authentication protocol (LPUF)-U-2 was proposed to provide security and prevent all possible attacks. However, it is discovered that a type of desynchronization attack can successfully break the proposed scheme. To overcome the vulnerability against desynchronization attacks, we propose here a new ultra-lightweight RFID two-way authentication protocol based on stream cipher technology that uses only XOR. The stream cipher is employed to ensure security between readers and tags. Analysis shows that our protocol can effectively resist position tracking attacks, desynchronization attacks, and replay attacks.

关键词： RFID   tag quantity estimation   clustering methods  

摘要： Accurate tag quantity estimation is a prerequisite to maximize the throughput of radio frequency identification (RFID) systems. Previous estimators, mainly designed for single-antenna RFID systems, often suffer from performance degradation in low signal-to-noise-ratio (SNR) regimes, making them inappropriate for multi-antenna RFID systems where received tag signals are likely to overlap. In this regard, a high-dimensional tag quantity estimator is proposed in the multi-antenna context by exploiting the spatial diversity at receive antennas. We first show that the collided tag signals can be rearranged as high-dimensional vectors, whereby the tag quantity estimation problem can be modeled as a high-dimensional data clustering one. We next prove that when the SNR on each backscattering subchannel is greater than 3 dB, the distance incrementation between clusters offered by the modeling advantage benefits their separation. This finding encourages us to integrate the density-based spatial clustering of applications with noise (DBSCAN) algorithm with this high-dimensional space for tag quantity estimation, and its superiority over several existing approaches are supported by both synthetic and real-world case studies.

关键词： Bit Replacement Operation (BRO)   Mobile System   Mutual Authentication   Radio Frequency Identification (RFID)   Ultra-Lightweight  

摘要： In the traditional RFID system, the secure wired channel communication is used between the reader and the server, and the new mobile RFID system is different from the traditional RFID system. The reader and the server communicate based on the wireless channel. This makes authentication protocols applicable to traditional RFID systems not applicable to mobile RFID systems. To solve this defect, a two-way authentication protocol MSB is proposed for ultra-lightweight mobile radio frequency identification system based on bit replacement operation. MSB (most significant bit) encrypts information based on bitwise operations, and the amount of computation of the communication entity is reduced. Tags, readers, and servers first authenticate and then communicate. MSB can be resistant to common attacks. The security analysis of the protocol shows that the protocol has high security attributes, and the performance analysis of the protocol shows that the protocol has the characteristics of low calculation volume. The formal analysis of the protocol is given based on GNY logic.

关键词： IoT   Tracking systems   RFID   Smart node   Energy consumption   Optimization   Simulation and experiment   Data collection   Clustering  

摘要： COVID-19 surprised the whole world by its quick and sudden spread. Coronavirus pushes all community sectors: government, industry, academia, and nonprofit organizations to take forward steps to stop and control this pandemic. It is evident that IT-based solutions are urgent. This study is a small step in this direction, where health information is monitored and collected continuously. In this work, we build a network of smart nodes where each node comprises a Radio-Frequency Identification (RFID) tag, reduced function RFID reader (RFRR), and sensors. The smart nodes are grouped in clusters, which are constructed periodically. The RFRR reader of the clusterhead collects data from its members, and once it is close to the primary reader, it conveys its data and so on. This approach reduces the primary RFID reader's burden by receiving data from the clusterheads only instead of reading every tag when they pass by its vicinity. Besides, this mechanism reduces the channel access congestion;thus, it reduces the interference significantly. Furthermore, to protect the exchanged data from potential attacks, two levels of security algorithms, including an AES 128 bit with hashing, have been implemented. The proposed scheme has been validated via mathematical modeling using Integer programming, simulation, and prototype experimentation. The proposed technique shows low data delivery losses and a significant drop in transmission delay compared to contemporary approaches.

关键词： Elecrically small antenna   Flexible substrate   Optimization   RFID  

摘要： This paper proposes a UHF flexible passive tag antenna for Radio Frequency Identification (RFID) which operates at 902-928 MHz frequency band. As main contribution, we design an electrically small and slim tag antenna by using a flexible commercial substrate. The small antenna has dimensions of 13 mm x 28 mm x 0.35 mm. The geometry of the tag antenna was optimized, using a Genetic Algorithm, to maximize its read range. The antenna performance was evaluated on flat and curve surfaces, by means of simulations of input impedance, reflection coefficient, gain and read range. Measurements of reflection coefficient were also developed. Results prove that the tag antenna can be wrapped on cylindrical surfaces with read ranges above one meter, suitable for applications related to industrial asset management, access control and identification of small objects such as hardware tools, tin cans, spray bottles and tin PET cylindrical containers.

关键词： Backscatter radio   harmonic RFID systems   NFC tags   RFID   RFID sensors  

摘要： Radio-Frequency IDentification (RFID) devices and sensors are among the main innovations of the last years, with an enormous impact on the Internet of Things (IoT) physical communication layer as well as on logistics and robotics. The aim of the present paper is to review the main technologies available for RFID sensors, and to identify the corresponding state-of-the-art when these technologies are applied to realistic IoT scenarios. Firstly, the concepts of radio bascattering and harmonic bascattering are analyzed, highlighting the pros and cons of each approach. Then, state-of-the-art solutions are reported, and the performance of each of them are discussed, to provide an overview of the potential of RFID-based sensing in different scenarios.

关键词： Waveguide and microwave transmission line components   Single antennas   RFID systems  

摘要： Here, a 'truncated C'-shaped planar coupled line resonator for UWB retransmission-based chipless RFID has been presented. The resonator is small compared to other existing resonators in the retransmission-based chipless RFID family. Two different coded multi-resonator prototype tags have been designed and validated with newly designed planar microstrip fingertip-shaped antennas. A good agreement is found between simulation and measurement responses. From the system validation, different coding combinations have been extracted when all resonators are present (111111111) and when three resonators are absent (110110101). It is found that with this resonator, 9 bits can be imposed instead of the existing planar rectangular resonator that gives only 1 bit with a larger size. Hence, as much as 86.7% of the occupied area is reduced by the resonator presented in this work. This work is anticipated to motivate the researchers in developing UWB passive RFID tags with higher bit density and smaller sizes for item tagging and sensing applications.

关键词： Chipless tag   Circularly polarized   Gas sensor   Humidity sensor   Low-cost, MWCNT  

摘要： With the increasing air pollution each day, it is very important to keep a check at the air quality we are breathing in. This can be made possible by designing an environmental sensor that is low-cost, robust, readily available, and easy to manufacture. In this research work, we propose a 12-bit smart chipless radio frequency identification tag having a radius of 7.4 mm. The miniaturized chipless RFID multi-sensor is based on humidity sensitive Kapton (R) HN substrate with Copper as a radiator. These materials selection enable the vast adaptability of this sensor in such areas where the use of a commercial environmental sensor is not economically supportive. The frequency response of the tag contains twelve uniquely identifiable frequency resonances in a 4-18 GHz frequency band. The gas sensing characteristic is incorporated by deploying multi-wall carbon nanotubes over the center of the tag design. The changes in the frequency response of the central slot due to CO2 concentrations are demonstrated in a radar cross-section graph. The proposed tag shows a reliable performance under changing atmospheric conditions. (C) 2001 Elsevier Science. All rights reserved.