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关键词： water bottles   impedance transformer balun-like integrated UHF RFID tag antenna   tag chip   baluns   long range detection   UHF antennas   radiofrequency identification   impedance matching   balun-like arms   Single antennas   RFID systems   dielectric materials   reasonably good radiation resistance   flexible range   compact UHF RFID balun-like integrated tag antenna   long read range  

摘要： A compact, flexible, long-range, and impedance transformer balun-like integrated UHF RFID tag antenna is proposed for the detection of water bottles. To alleviate the performance of a tag antenna in close proximity to a high dielectric material such as water, the radiating element of the tag antenna uses folded, unbalanced strips made of balun-like arms wrapped around the tag's body. As a result, a wide bandwidth with reasonably good radiation resistance is achieved. The tag's body comprises dual loops for the impedance matching to the tag chip. This leads to a long read range of 13.33 m;>5.83 m compared to other state-of-the-art designs. The proposed tag antenna conforms to a small footprint by wrapping the balun-like arms around the tag's body, which results in a compact form. The tag is fabricated, and the results reasonably agree with simulations.

关键词： Artificial intelligence (AI)   deep learning (DL)   long short-term memory neural network (LSTM-NN)   machine learning (ML)   near-field (NF) focusing   NF focused (NFF) array   radio frequency identification (RFID)   RFID gate   RFID portal   support vector machine (SVM)   ultrahigh-frequency (UHF)-RFID  

摘要： This article introduces a new radio frequency identification (RFID) gate for access control merging the benefits of near-field focusing and deep learning (DL). The gate uses a near-field (NF) focused antenna with a slight tilted beam to create an asymmetrical reading volume, which is essential to determine the direction of tag transit with a single antenna. The power and phase of the signal backscattered from the tag are used as features for classifying tag status: crossing, static, or moving around the gate yet not crossing it. The antenna is made up of a 3 x 3 array of circularly polarized resonant patches, operating at the ETSI RFID band (865-868 MHz). After validating the coverage volume of the antenna, tag data were used to train a multiclass support vector machine (SVM) and a long-short term memory neural network (LSTM-NN). The appropriately sized LSTM-NN yields 98% classification accuracy in a scenario emulating a realistic shop entrance. The solution offers improved robustness to multipath effects and reduced false positives compared with conventional RFID gates using phased array antennas, two closely spaced portals, or bulky electromagnetic screens or absorbers, at lower cost and with a simpler infrastructure.

关键词： Alpine stream monitoring   bedload transport   geophone monitoring   pebble virtual velocity   RFID pebble tracking  

摘要： Monitoring bedload transport in rivers is a challenging research domain teeming with technical innovations and methodological developments aimed at improving our knowledge and models of bedload processes at different spatial-temporal scales. Radio frequency identification (RFID) technology has improved sediment tracking, allowing the characterisation of transport processes of individual particles at flood-event scales. Meanwhile, geophone sensors have enabled the long-term continuous monitoring of seismic signals that can provide surrogate measures of bedload fluxes at local scales, during flood events and at sediment-pulses. The combination of these two techniques could allow sediment transport processes to be linked with both flood events and sediment pulses. In this study, we used a combination of active ultra-high frequency RFID technology and geophone monitoring stations to link the virtual velocity of tracers with seismic activity, hydraulic forcing, and the properties of the tracked particles. Single and multiple regression models show that seismic activity best explained the observed variance (81%) of the virtual velocity of particles, in comparison with discharge (58%) and stream power (63%). Furthermore, when several control variables (seismic activity and particle properties) were combined in an empirical model, the model explained 89% of the variance and allowed quantification of the portions of the variance explained by hydraulic forcing, geophonic activity and tracked particles. These results show the high potential of these combined monitoring techniques for future in-field experiments to investigate bedload processes at different spatiotemporal scales in rivers of different morphologies.

关键词： Software-Defined Radio   Radio definida por software   SDR   RDS   Spectral Signature   Firma Espectral   ADALM-PLUTO   Chipless   Etiqueta sin chip   RFID   SpuR  

摘要： To solve problems related to Radio Frequency Identification, as well as to develop new technologies and applications with chipless RFID tags, this article describes the development of an innovative reader system based on Software-Defined Radios. Called SpuR, the system proposes a method of reading the spectral signature of RFID tags chipless, using general purpose hardware, reconfigurable by software, and operating in a wide frequency range without the need to change the reading equipment. This approach allows the accurate reading and identification of different types of chipless tags, using a classification procedure, by Euclidean distance, comparing them with a previously stored database.

关键词： Wireless communication   Technical requirements   Frequency modulation   Radio transmitters   Receivers   Microwave communication   Reliability   Radiofrequency identification   Fourth Industrial Revolution  

摘要： With the increasing popularity of industry 4.0 applications and the integration of network-capable small devices into the Internet of Things (IoT), the technical requirements for the transmission of information are also rising. High reliability is needed, especially for wireless systems used for industrial applications. One of the biggest challenges in this context is multipath propagation. Ultrahigh frequency radio-frequency identification, or UHF RFID for short, has proven to be a reliable technology for reading and transmitting data. In this communication system, the data records to be transmitted are modulated by a transmitter (reader) to an electromagnetic alternating field with a frequency between 860 MHz and 960 MHz and serve the receivers (transponders) not only for information transmission but also for energy supply.

关键词： Fabrication  

摘要： The fabrication of flexible antennas for RFID applications can be divided into subtractive and additive methods. In this study, a low-cost additive method is proposed, which involves printing aluminum paste and utilizing a galvanic replacement reaction. Through a galvanic replacement process, copper sulfate waste effluent was employed to convert the aluminum electrode into a highly conductive copper electrode. The physical characteristics of the Cu electrode, such as surface flatness, thickness, and Al-Cu conversion ratio, were studied. The Cu electrode, produced using an innovative additive technique at a temperature of 75 degrees C for 15 minutes, exhibits the lowest resistivity of 5.89 x 10-8 omega m. This resistivity is comparable to that of a commercial silver thick film electrode, making it suitable for use in manufacturing RFID antennas for RFID module applications. With an S11 of -40 dB at 1.26 GHz, a maximum gain of 2.87 dBi, a maximum efficiency of 53.63%, and a reading distance of 9 meters, the RFID module demonstrates impressive performance. The reading distance of an RFID module with a copper foil antenna is longer (8.5 meters).

关键词： Information management  

摘要： This paper presents the development and implementation of an innovative Internet of Things (IoT)-based RFID attendance system integrated with a module focused on curbing the spread of contagious diseases in densely populated settings, such as schools and workplaces. Recognizing the limitations of existing radio frequency identification (RFID) attendance systems, an extensive analysis of prior works was conducted to identify crucial functionalities necessary for an effective solution. Leveraging the IoT paradigm, we devised a 3-layer architecture encompassing thermometer sensors, RFID technology, Arduino microcontrollers, Wi-Fi connectivity, and the message queuing telemetry transport (MQTT) protocol to facilitate seamless data transmission and storage. The resulting prototype enables real-time monitoring of feverish symptoms, serving as an early warning system for potential contagious illnesses while streamlining attendance management. Data collected from the IoT devices is securely stored in a centralized database and accessed through an intuitive information system embedded within the IoT application. Users can effortlessly view and manage attendance data, while administrators gain access to health-related metrics, enabling timely responses to health concerns. User evaluations of the developed system resulted in an outstanding "A" rating, validating its reliability, functionality, and user satisfaction. Future improvements involve real-world testing, scalability assurance, integration with health authorities for comprehensive data management, and automated alerts for potential disease outbreaks. © 2023 by the authors of this article.

关键词： Battery-less radio-frequency identification (RFID)   priority strategy   time efficiency  

摘要： Radio-frequency identification (RFID) technology by transmitting radio waves to the target area and attaching to the object battery-free RFID tags. It can accomplish the fast, timely, and accurate acquisition of the relevant data of the object without touching the identified object. In practical applications, there may be problems where products that have not been warehoused are missing, which we call a missing unknown tag problem. The existing missing tag identification methods are not well suited to the scene, and the missing tag identification method containing unknown tags only takes into account the problem of known tags and unknown tags appearing in the same area and cannot solve the problem of these missing unknown tags. Therefore, we propose a priority-based strategy for missing unknown tag identification (PMUTI), which improves the identification process by means of the priority strategy. The method of sequential marking for unknown tags that have been missing is convenient for warehouse managers to make quick judgments and processing. The experimental results show that the PMUTI outperforms existing methods.

关键词： Battery-less radio frequency identification (RFID)   time efficiency   unknown tags  

摘要： Radio frequency identification (RFID) technology is widely used in warehouse management and supply chain management. In the actual application, unknown tags, such as newly added or incorrectly placed products, will be placed into a certain area of the warehouse. Existing identification protocols can identify such unknown tags by collecting tag IDs and comparing them with backend server. Alternatively, the known tags can be filtered through the filter vector to prevent interference from unknown tags and improve identification efficiency. However, there is a lack of consideration of the collision impact on identification efficiency. In this article, we introduce the bit tracking technology to accelerate the identification process and propose a bit-tracking-based strategy for unknown tag identification (BTUTI) protocol. We solve the problem by means of known tag deactivation and unknown tag identify. First, by adopting bit tracking technology, the reader can easily locate the positions of the collision bit. By hashing the tags of these collision slots, the collision slots can be turned into resolvable slots, thus improving the utilization rate of slots. Second, in the expected nonempty slot, the reader can send command to deactivate the known tag and skip empty slots and irresolvable collision slots. The experiment proves that BTUTI can increase the time efficiency compared to the state of the art.