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关键词： Backscattering   RFID   Passive Tag   ASK   Energy Maximization   BER   Optimization  

摘要： The radio frequency identification (RFID) passive tag is wireless communication device with high energy sustainability, such that it uses the incident radio frequency (RF) signal to backscatter its information. This paper investigates the output load power maximization with optimal load impedances selection in the backscatter communication (BackCom) network. The considered BackCom system comprises a reader broadcasting an unmodulated carrier to the passive tag in the downlink. The tag backscatters its information signal to the reader with binary amplitude-shift keying (BASK) modulation in the uplink. We formulated an average output load power maximization problem by jointly optimizing the reflection coefficients while satisfying the minimum bit error rate (BER) requirement and tag sensitivity constraint. To simplify the problem, we transform the BER constraint to the modulation index constraint and reduce the 4 variables problem to 2 variables convex optimization problem. Using the Karush-Kuhn-Tucker (KKT) conditions, we design an algorithm to obtain the closed-form expression for the global optimal reflection coefficients that maximize the output load power. The simulation results provide insight into the impact of the information bit probability, tag sensitivity constraint, and BER on the achievable average load power. An overall gain of around 16% signifies the utility of our proposed design.

关键词： Antenna measurements   Time-domain analysis   Frequency-domain analysis   Antennas   Mathematical models   Aluminum   Clutter   Chipless RFID tag   clutter   frequency domain   parasitic reflections   vector fitting (VF)  

摘要： In a frequency-domain chipless RFID system, the backscattered signal from a tag is directly obtained in the frequency domain over limited bandwidth. However, to reduce the parasitic reflections, it is crucial to obtain the backscattered signal in the time domain. This letter proposes a precise quasi-analytic method, known as the model-based vector fitting (VF) technique, to provide the closed-form equation of the backscattered response in the time domain. The proposed method successfully recovers a tag's identification (ID) among parasitic reflections using a single tag measurement without requiring prior knowledge about the tag.

关键词： attribute-based encryption   body-area Internet of Things   cybersecurity   healthcare Internet of Things   Near Field Communication   point-of-care   proxy re-encryption   radio frequency identification  

摘要： World population and life expectancy have increased steadily in recent years, raising issues regarding access to medical treatments and related expenses. Through last-generation medical sensors, NFC (Near Field Communication) and radio frequency identification (RFID) technologies can enable healthcare internet of things (H-IoT) systems to improve the quality of care while reducing costs. Moreover, the adoption of point-of-care (PoC) testing, performed whenever care is needed to return prompt feedback to the patient, can generate great synergy with NFC/RFID H-IoT systems. However, medical data are extremely sensitive and require careful management and storage to protect patients from malicious actors, so secure system architectures must be conceived for real scenarios. Existing studies do not analyze the security of raw data from the radiofrequency link to cloud-based sharing. Therefore, two novel cloud-based system architectures for data collected from NFC/RFID medical sensors are proposed in this paper. Privacy during data collection is ensured using a set of classical countermeasures selected based on the scientific literature. Then, data can be shared with the medical team using one of two architectures: in the first one, the medical system manages all data accesses, whereas in the second one, the patient defines the access policies. Comprehensive analysis of the H-IoT system can be useful for fostering research on the security of wearable wireless sensors. Moreover, the proposed architectures can be implemented for deploying and testing NFC/RFID-based healthcare applications, such as, for instance, domestic PoCs.

关键词： chipless RFID   hexagonal resonator   phase coding   size reduction   S-parameters  

摘要： A chipless RFID tag was designed using two hexagonal resonators. By defining a relation for the phases of S-parameters and rotating the resonators around their axes, a senary coding scheme was obtained at the resonant frequency. The designed resonator was able to generate six different codes using six different phase parameters at 3.03 GHz. While the conventional binary ("0" and "1") coding of ordinary tags makes minimal use of bandwidth capacity, the senary coding in the proposed design allowed the use of a larger bandwidth capacity. Requiring much fewer resonators for generating more codes, the proposed technique leads to significantly smaller tags. Using the proposed tag with two resonators, 6(2) = 36 different codes can be generated;more generally, an n-resonator tag of the proposed type can create 6(n) different codes.

关键词： Unmanned Traffic Management   UTM   UAS   Mining   RFID   Smart-tag   RSSI   RTLTS   Localization   Non-GPS   SAFE50  

摘要： Enterprise Unmanned Traffic Management is a holistic system concept evolving from technological developments in radio frequency where dynamic tracking can be added into current and emerging platforms. This is done through inexpensive RF sensors capable of real-time and cooperative, non-GPS tracking enabling digital visualization of assets, including unmanned aerial systems (UAS). The RF sensors are low size, weight, and power (SWaP), creating efficiencies in energy and material consumption while transmitting positions in real-time and at long ranges. Multiple UAS and other unmanned vehicles can be visualized for risk mitigation in operations, thus allowing mine management better decision-making capabilities in the current and future mosaic of mine operations.

关键词： Parking management system   Smart parking   Multi-objective decision-making method   MODM-RPC  

摘要： Due to the tremendous progress in the automotive industry, the growth of the urban population, the number of cars is increasing and this creates parking challenges. Intelligent parking management systems offer an optimal solution for finding empty parking spaces so that drivers can quickly find their car parking spaces. To solve these issues, it is necessary to design an intelligent parking system, besides providing comfort to drivers, which is also economically viable. In this paper, an intelligent multi-storey car parking management system called MODM-RPCP is proposed with the help of RFID technology and user preferences review, which effectively solves car parking issues. The MODM-RPCP approach is a multi-objective decision-making method that reduces the problem of average booking time and response time of the central parking management server. The simulation results show that the MODM-RPCP reduces the average booking time by more than 19.2 and 27.1%, and decreases the response time of the central parking management server more than 20.1 and 29.78% compared to MOGWOLA and ODPP approaches.

关键词： Wearable   Printed sensor   Printed antenna   Antenna performance   Sintering process   Pad printing  

摘要： Many different parameters affect the antenna performance of the wearable sensors. In this study, antenna per-formances of textile based sensors which have different pass numbers from 1 to 5 printed using conductive ink with pad printing method were investigated. Moreover, the effect of sintering process after printing on the RF antenna performances of wearable sensors was examined. For this, antenna impedances, and reflection co-efficients of the sintered, and non-sintered printed sensors were measured using a vector network analyzer. While the frequency at the collapse point of the reflection coefficient graph of the sensors without sintering and with different pass numbers was 254 MHz, the collapse point of the reflection coefficient graph of the sensors was 943 MHz after sintering. The measurements indicate that the sintering process has a significant effect on the antenna performances of wearable sensors, and it is concluded that the sintered printed wearable sensor samples enable data transmission wirelessly in short range. In addition, bending, and gain measurements was applied to wearable sensor which has the best performance according to the impedance measurement results. Thus, these UHF-RFID enabled wearable sensors with antenna performance might be good option to form a network of passive interactive sensor architecture for RFID and wearable technologies. In addition, considering the designed wearable sensor structure, it is foreseen that the potential usage areas of this structure may be moisture sensitive areas (such as supply chains and transportation of moisture-sensitive products).

关键词： balun structure   double-sided parallel-strip lines   four-way power divider   UHF antennas   switching diodes   radiofrequency identification   switchable far-field   dipole antenna arrays   electromagnetic wave polarisation   high-performance UHF RFID reader antenna   balanced structure   ultra-low profile   far-field operative modes   antenna feeds   baluns   central magnetic field   power dividers   near-field working state   antenna radiation patterns   strip lines   near-field operative modes   reconfigurable feed network  

摘要： An ultra-low profile and high-performance UHF RFID reader antenna is proposed in this letter, which can be switched between far-field (FF) and near-field (NF) operative modes. This antenna is composed of four dipoles and a reconfigurable feed network. The four dipoles form a square, and the feed network is located in the centre. The feed network is a four-way power divider, and the phase of the output signal can be controlled by switching diodes. As a balanced structure, double-sided parallel-strip lines (DSPSLs) are used to feed four dipoles. Compared to the balun structure, the application of DSPSLs can reduce the area of the feed network, thereby reducing the influence of the feed network on the central magnetic field. Experimental results show that the proposed antenna can provide a NF reading area of 180 x 180 mm(2), and the identification rate can reach 100% within 30-60 mm height. The FF gain of the antenna is 4.7 dBic, and the overlapping range of 3 dB AR bandwidth and -10 dB impedance bandwidth is 800-960 MHz. The good FF and NF performance of this antenna is conducive to its application in RFID systems.

关键词： Hybrid coding   Open stub resonator   RFID   Spectral signature  

摘要： A novel spectral signature Chipless Radio Frequency Identification (RFID) tag is designed, fabricated, and validated as a barcode replacement for Fifth Generation (5G) supply chain-based Internet of Things (IoT) scenarios. The tag displays a low profile of 12.7 × 13.9 mm² with radiating data capacity of 32 bits. The design includes a hybrid On-Off and frequency shift keying technique to enhance the data encoding functionality. The unit tag translates 1:1 slot-to-bit by integrating an open stub L structure as a resonating assembly. Further, hybrid encoding has been incorporated to enhance the ratio up to 1:3, which leads to a 3ⁿ⁽2ⁿ-1) data pattern. As a result, the Chipless RFID tag offers a noticeable density per frequency of 4.6 bits/GHz for a 3.1–10.9 GHz spectral variation. The design is carried out over a flexible substrate, Taconic TLX-0, and the results exhibit fair agreement between simulated and measured results. Further, tag performance is validated by placing it on different objects: books, silver cups, and wooden boxes. © 2022 Karabuk University

关键词： 3-D-dipole antenna   conductive material   metal plate   reading distance   RFID tag antenna  

摘要： A novel compact 3-D-dipole antenna for a radio frequency identification (RFID) tag is presented in this article. The proposed antenna enables the tag to be read when mounted on surfaces composed of electrically conductive materials. A close match between the input resistance and reactance of the antenna to the desired conjugate impedance of an Alien Higgs-4 chip (8.2 - j 148.5 Omega at 925 MHz) can be achieved by controlling the C-arm length and the width of the 3-D dipole. Experiments demonstrated that when an RFID tag antenna is attached to a conductive surface, a 0.2 mm gap between the antenna and the conductive plane enhances the antenna's gain by increasing reflection from nearby surfaces (e.g., a metal object, a container of water, and a human wrist) within range of the antenna. Maximum read ranges are measured for the tag antenna fabricated with dimensions of 32 x 25 x 3.2 mm(3) (0.10 lambda(0) x 0.08 lambda(0) x 0.01 lambda(0)) and mounted on various materials and objects. In an outdoor environment, an effective isotropic radiated power (EIRP) transmitted by the RFID reader of 4.0 W achieves the maximum reading distances of 5.1, 3.3, and 3.9 m when the proposed tag antenna is placed on a metallic plate, a container of water, and a human wrist, respectively. The experiment and simulation results have a good agreement with each other.