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Determining an accurate circuit model for the chip of an RFID card is a complex task. We identify the prior work carried out to characterize such a chip and introduce a novel de-embedding method that provides higher accuracy through using a simple two port network. Additionally, a practical implementation of such a method is investigated and verified through measurements. Finally, the equivalent RC...
An impedance matching method applicable to UHF-RFID tags mounted on optical discs, where the main radiating element is the disc metallic layer (from now on optical disc-based tags) is presented in this paper. Such a method provides a very simple analytical approach and allows us to obtain any arbitrary matching level at the desired frequency, by using only one reactive element as a matching network...
A novel planar and electrically small (0.1×0.1×0.002λ3) RFID tag antenna is proposed whose radiation pattern is near-3D omnidirectional. The proposed antenna is comprised of a small loop and an open-loop element with an inverted Z-shaped slot on it. The inverted Z-shaped slot is used to make the antenna smaller and improve the radiation performance. The proposed antenna is easy to change its shape...
Wireless sensing with UHF RFID tags gets attention in the last years. Some systems integrate sensor components on the tag beside the RFID chip. For this application type a patch antenna that integrates sensor components and the RFID chip in openings in the top and the bottom patch has been developed. The antenna is presented and an analysis of the size and the placing of the openings to the gain and...
A design procedure of a special UHF RFID tag antenna is presented in this paper. The final antenna is matched well with the ST Microelectronics XRAG2 chip at the intended resonant frequency with bandwidth of 33 MHz and has omni-directional beam patterns with gain of 1.86 dBi. A prototype has been successfully fabricated, tested by Rohde & Shwarz ZVB Vector Network Analyzer and showed good fit...
In this paper, a passive RFID tag antenna in UHF band (860MHz-960MHz) using a meander split ring like a gear and an electricity small loop is proposed. Inductively coupled feed method is used to broaden the bandwidth. The proposed structure not only successfully reduces the tag size but also achieves impedance match between the antenna and the chip directly. Especially by varying their size, the antenna...
An analytical framework for evaluation of platform-tolerance of RFID tags is developed and the potential platform-tolerance achieved with high-resistance tag antennas is demonstrated. A method for transforming the predominantly capacitive and low-resistance tag chip impedance for matching with this type of antennas is also proposed.
A fully metallic ink-jet printed passive chipless RFID tag on paper substrate is presented. The tag consists of an ultra-wide-band antenna, a microstrip transmission line with distributed shunt capacitors as information coding element which is reconfigurable by ink-jet printing process. Tapered microstrip line is employed to overcome the limitations of low conductivity and thin film thickness of ink-jet...
Worm propagation model is an important issue in network information security. Based on the knowledge of infectious disease dynamics, the major methods to research worm propagation are related to some characteristics of network, such as topology, traffic, user behavior. In 2008, with the transformation of key antivirus work from the terminal PC to network server group, the industry put forward a novel...
This paper proposes a design of a power harvester for a semi-passive RFID tag. A tunable impedance transformation circuit is inserted between the antenna and the rectifier unit to maximize the power delivered to the rectifier of a tag and minimize reflections from the antenna input port. A power harvester for the UHF band of 950 MHz has been designed based on a 0.35 mum CMOS technology. This impedance...
In the case of short reader-to-tag distances, shunt resistance diverts current in order to protect the chip but this affects the chip power supply and the delta radar cross section. This paper presents a shunt resistance law variation which keeps a constant power supply in the RFID chip and the impact of this law on the delta radar cross section.
This paper presents the RFID tag antenna design for the frequency band of 920-925 MHz corresponding to the standard of UHF RFID in Thailand. An importance for design the tag antenna is that the impedance of the tag antenna must be conjugately matched with the impedance of the IC chip for the maximum power transfer from the tag antenna to the IC chip. The tag antenna can be easily designed and easy...
In this paper, we discuss change of read range between a UHF passive RFID tag and reader when a tag is close to another tag. The read range is determined by the strength of forward link and reverse link, which are represented by received power at a tag and reader, respectively. Approaching of tags causes electromagnetic interference between antennas of tags and results in change in impedance matching...
This paper presents a review of RFID tag antenna design and some examples. After introduction of related theory, three design examples are provided. First, the inductively-coupled tag antenna is presented for its capability of matching to any commercial chips with simple adjustment of two design parameters. Second, the inductively-coupled tag antenna having isotropic RCS patterns is presented. Its...
Low cost, low profile and miniaturized size are the most critical factors needed to consider in the design of antennas for RFED applications. For maximum power transfer, the input impedance of the antenna must be the conjugate of input impedance of the ASIC. In this paper, we present a novel folded dipole antenna with a very simple configuration. The required input impedance can be achieved easily...
A low cost novel antenna for radiofrequency identification (RFID) tags mountable on metallic surfaces has been proposed and implemented. The proposed antenna indicates not only an easy impedance matching method with various microchip impedances but also the ability to be mounted on metallic surfaces. In this paper, the folded dipole type tag antenna with two parasitism-patches is proposed. This allows...
In this paper, three different types of frequently used antennas in passive RFID tags with different sizes are investigated for voltage scavenging application. Most critical is to create a minimum voltage at the antenna port. Therefore, using simulations with two software packages, CST and HFSS, a detailed explanation is presented of the induced voltage at the antenna port versus antenna length and...
A high intercept points, cost-effective, and power-efficient switching FET double balanced mixer (DBM) is reported. The Switching FET DBM demonstrated in this work offers input intercept points (IIP3) and conversion loss typically 44 dBm and 8.5 dB respectively with 15 dBm LO power for the frequency band (RF: 900-2150 MHz, LO: 850-1950 MHz, IF: 50-200 MHz). The measured interport isolation is typically...
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