教学课程资源库 更多>>

关键词： Circular polarization   RFID systems   Antenna   Wireless communication  

摘要： In this article, a novel ultra-high frequency radio frequency identification (UHF RFID) reader antenna is proposed and experimentally investigated. The proposed RFID antenna design consists of three layers;the first layer has a ring shape with a feeding line at the center, the second layer has a small periodic structure that affects the radiation performance of the antenna, and the third layer has a bent metal structure. The final design, with the dimensions of 129.2 mm x 129.2 mm x 26 mm, yields a 10-dB impedance bandwidth of 34 MHz (854-889 MHz) and a 3-dB axial-ratio bandwidth of 118 MHz (857-975 MHz). The antenna is fabricated and tested for its RF parameters and RFID metrics. In performance tests, ISO 18000-63 and Gen2v2 compatible RFID reader and tags are used. RFID tag reading tests have been successfully performed under specified communication protocols without any operational failure while providing RF communication. The measured results prove the technical potential of the proposed antenna to possess good RF performance in RFID based wireless networks.

关键词： Circular polarization   Feed network   Reader   RFID   Ring antenna  

摘要： In this paper, a compact, lightweight, low-profile dual-band circularly polarized antenna is presented for handheld radio frequency identification (RFID) readers. The proposed antenna consists of two concentric hexagonal rings and a feed network printed on different layers of the dielectric substrate. The antenna configuration exploits a stacked-coupled technique for gain enhancement and single-port feeding for easy manufacturing. The center frequencies of the two resonating bands are 0.92 GHz (UHF) and 2.45 GHz (ISM). The antenna exhibits circular polarization characteristics in both the resonating bands, therefore encountering the losses due to polarization mismatch and increasing the tag detection reliability. A prototype of the proposed RFID antenna is simulated and fabricated, and experimental results are in close agreement. The peak antenna gain is 3.3 dB and 5 dB in the UHF and ISM bands, respectively. The overall size of the RFID antenna is 80 mm x 80 mm x 7.76 mm.

摘要： For many faiths and especially for Muslims, Mecca as well as Kaaba, hold a spiritually important place. Although communication takes place in the form of either human to human or human to the device, however, internet's great future is promised by the internet of things (IoT). Machines as well as computers identify the objects along with metadata recording or using radio waves to control individual targets with the help of a Radiofrequency identification system (RFID), which is an automatic technology. This paper aims to propose an RFID based IoT framework for monitoring pilgrims vital along with health signs by engaging them with slice during Hajj. Facilitation regarding detection as well as monitoring of Personal RFID data of pilgrims is the result of this system.

关键词： radiofrequency identification   radiofrequency oscillators  

摘要： A frequency generator based on the forward coupler principle is proposed. The proposed design, intended for high-frequency applications, uses Half-Mode Substrate Integrated Waveguide structure to realise the forward coupler. It thus achieves compactness, requiring approximately half the area compared to Substrate Integrated Waveguide structures, and supports non Transverse Electromagnetic (TEM) functionality. The non-TEM environment provides the flexibility to use the frequency generator for chipless Radio Frequency Identification readers in the sub-GHz band and mm-wave range. Full-wave simulations and the subsequent measurements on a prototype developed on Rogers 3006 substrate performed for the forward coupler resonators and frequency generator validate the proposed design concept.

关键词： Wearable Antenna   RFID   X-band   Circular polarization   Flexible antenna   Radiation pattern  

摘要： A semicircle-shaped circularly polarized bidirectional flexible antenna is proposed for the X-band applications suitable for RFID and other wearable applications. Semicircle-shaped radiator with dimensions of 50 x 50 mm(2) is utilized for the development of X-band antenna over flexible woollen felt substrate. Woollen felt material with a dielectric constant (epsilon(r)) of 1.4 and a thickness of 1 mm is utilized for the construction of X-band antenna. Since circular polarization is more suitable for multipath fading environment, a slant rectangular slot is introduced in the radiator. The simulated antenna has an impedance bandwidth of 3.11 GHz ranging from 9.42 to 12.53 GHz. The prototype is fabricated and its impedance bandwidth, radiation pattern, gain, polarization and axial ratio (AR) are measured. The fabricated prototype antenna has a gain of 5 dBi at the center frequency of 10 GHz. From the measurements, it is evident that the proposed prototype is more suitable for RFID and other wearable applications.

关键词： Internet of things  

摘要： RFID (radio frequency identification) is an Internet of Things (IoT) enabling technology. All physical devices can be connected to the Internet of Things thanks to RFID. When RFID is extensively utilized and fast increasing, security and privacy concerns are unavoidable. Interception, manipulation, and replay of the wireless broadcast channel between the tag and the reader are all possible security threats. Unverified tags or readers provide untrustworthy messages. IoT requires a safe and consistent RFID authentication system. PUFs are also physical one-way functions made up of the unique nanoscopic structure of physical things and their reactivity to random occurrences. PUF includes an unclonable feature that takes advantage of physical characteristics to boost security and resistance to physical attacks. We analyze the security of the RSEAP2 authentication protocol that has been recently proposed by Safkhani et al., a hash-based protocol, and elliptic curve cryptosystem-based protocol. Our security analysis clearly shows important security pitfalls in RSEAP2 such as mutual authentication, session key agreement, and denial-of-service attack. In our proposed work, we improved their scheme and enhanced their version using physically unclonable function (PUF), which are used by the proposed protocol in tags. This research proposes a cloud-based RFID authentication technique that is both efficient and trustworthy. To decrease the RFID tag's overhead, the suggested authentication approach not only resists the aforementioned typical assaults and preserves the tag's privacy, but also incorporates the cloud server into the RFID system. According to simulation results, our approach is efficient. Moreover, according to our security study, our protocol can withstand a variety of attacks, including tracking, replay, and desynchronization assaults. Our scheme withstands all the 18 security features and further consumes the computation cost as 14.7088 ms which is comparable with

关键词： Radio frequency identification (RFID)  

摘要： The outbreak of COVID-19 has attracted people's attention to our healthcare system, stimulating the advancement of next-generation health monitoring technologies. IoT attracts extensive attention in this advancement for its advantage in ubiquitous communication and sensing. RFID plays a key role in IoT to tackle the challenges in passive communication and identification and is now emerging as a sensing technology which has the ability to reduce the cost and complexity of data collection. It is advantageous to introduce RFID sensor technologies in health-related sensing and monitoring, as there are many sensors used in health monitoring systems with the potential to be integrated with RFID for smart sensing and monitoring. But due to the unique characteristics of the human body, there are challenges in developing effective RFID sensors for human health monitoring in terms of communication and sensing. For example, in a typical IoT health monitoring application, the main challenges are as follows: (1) energy issues, the efficiency of RF front-end energy harvesting and power conversion is measured;(2) communication issues, the basic technology of RFID sensors shows great heterogeneity in terms of antennas, integrated circuit functions, sensing elements, and data protocols;and (3) performance stability and sensitivity issues, the RFID sensors are mainly attached to the object to be measured to carry out identification and parameter sensing. However, in practical applications, these can also be affected by certain environmental factors. This paper presents the recent advancement in RFID sensor technologies and the challenges for the IoT healthcare system. The current sensors used in health monitoring are also reviewed with regard to integrating possibility with RFID and IoT. The future research direction is pointed out for the emergence of the next-generation healthcare and monitoring system.

关键词： Mutual coupling reduction   radio frequency identification (RFID)   chipless RFID tag   Radar Cross Section (RCS)  

摘要： Compact chipless RFID tags suffer from the mutual coupling between neighboring elements that have close resonant frequencies. In such tags, it is difficult for the words including zero bits to be detected by a reader, leading to false detection. In this paper, two techniques to reduce the mutual coupling effect based on rearrangement of the extended elements with reduced size are proposed. These techniques are applied to a compact chipless RFID tag, which has several nested C-shaped strips placed on both surfaces of the substrate. Top and bottom strips are connected through vias, and slots are placed in the middle of the bottom strips. The resonant frequencies are adjusted by varying the slot lengths in the first technique and variable vias position in the second technique. Through these techniques, the neighboring resonant frequencies can be placed farther apart. In doing so, the stability of the RCS frequency response is improved, which enables a reliable reading where zero bits are coded. For a 9-bit tag, the radius of the substrate is 7.8 mm, equivalent to 0.097 lambda(g) operating over 2-9 GHz. A prototype is fabricated and measured.

关键词： Elliptic curve cryptography (ECC)   Internet of things (IoT)   RFID   Healthcare   Mutual authentication  

摘要： Given the ever-increasing advances in science and technology in recent years, the security and authentication issues using elliptic curve cryptography (ECC) have gained a lot of attentions especially for smart cards in a variety of networks, such as smart homes and medical-based care systems being based on the Internet of things (IoT). In systems such as health care, patient information is always crucial and no one should have access to this information. Recently, much research has been conducted in the area of security and authentication for medical care systems being based on the IoT using RFID technology. One of these schemes is the Alamr et al.'s protocol, which bears high computational cost for authentication between card and reader. In this paper, we have proposed a scheme based on ECC in order to establish a mutual authentication within RFID technology in the IoT. In the proposed scheme, computational cost, communication cost and elliptic curve point multiplication running time and data storage cost are investigated. Moreover, security requirements and various attacks have also been considered in the proposed protocols. AVISPA software has also been used for security analysis. The analyses represent that the proposed scheme has lower computational costs, lower communication costs and less elliptic curve point multiplication time compared with those of similar protocols. It has also resolved the security shortcomings of the RFID authentication protocol.

关键词： Counterfeit electronics   supply chain security   RFID   MEMS   hardware authentication   pyroelectric energy harvester   bulk acoustic resonator   microstrip antenna  

摘要： This paper describes a proof-of-concept sensor (1) that can detect and record (without battery) a semiconductor-chip tamper activity (i.e., de-soldering followed by mechanical banging) which a counterfeiter does to scavenge semiconductor chips from a printed circuit board and (2) that can be wirelessly interrogated without need to open semiconductor packages. The sensor is based on a High-overtone-Bulk-Acoustic-Resonator (HBAR) working as a Radio-Frequency Identification (RFID) tag, which can be permanently broken down by the voltage and charge generated by a pyroelectric-energy-converter (PEC). The concept is demonstrated through connecting a 7.5 GHz HBAR (based on a 350 nm-thick ZnO thin film deposited on sapphire) to a 5 x 5 x 0.15 mm(3) lithium niobate-based PEC, via a Kapton-copper cantilever switch. When the switch is turned on (due to a mechanical shock emulating a counterfeiter's mechanical banging), the accumulated charge on the PEC (produced by 250 degrees C temperature rise emulating a counterfeiter's de-soldering) generates an electrical pulse with 9.6 V peak voltage and 1.36 nC charge transfer to an 8 M Omega load (close to the HBAR's resistance). The PEC's voltage and charge are shown to permanently breakdown the ZnO film on the HBAR (0.1 x 0.1 x 0.33 mm(3)) having a quality factor (Q) of about 2,500, so that the Q drops to near zero, drastically changing the RF absorption/scatter characteristics. A wireless interrogation is demonstrated by having a pair of 2 x2 x 0.2 cm(3) microstrip patch antennas, one of which is connected to HBAR while the other one is connected to a network analyzer working as a wireless interrogator.