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Radio frequency identification (RFID) sensors are increasingly recognized as the way for achieving smart environment monitoring. Real world industrial applications, such as multiobjects orientation detection, motion sensing as well as monitoring in harsh environment require real-time operation and fast responses for control decisions. This paper examines the timing analysis of UHF networked RFID sensors tag system and the factors influencing time latency. Time constrains in RFID communication channel, such as the minimum detection time of the reader in the vicinity of the RFID tag and the effect of protocol requirements are examined experimentally for commercial tags in compliance with the European Telecommunications Standards Institute (ETSI) regulations. This assessment has the objective to analyze the RFID tag for instance as a motion sensor. In order to illustrate the interest of the presented delay analysis, a method to measure the response time due to rotation speed is introduced. A case study using two commercial RFID tags under rotation is presented and analyzed in terms of delays. [ABSTRACT FROM PUBLISHER]

Tag collision is one of the most significant limitations of the RFID systems. Current anti-collision algorithms process the problem in medium access control layer as an estimation of the collided tags number. This process requires retransmission of the RN16 sequence, and hence the discarding of signals in the PHY layer. This letter shows how to use the physical signal in order to decode collided tags. The contributions of this letter are as follows: 1) a simulation model of the Ultra High Frequency RFID system using a Nexxim circuit in conjunction with a system designer using Ansoft Designer simulator platform; 2) a proposed edge transition scheme to recover collision and decode tag signals. This scheme permits us to decode collision signal of three tags, which increases the system throughput from 0.37 (slotted Aloha) to 1.37; 3) an experimental setup that was able to collect and decode the real collision tag signal thanks to our proposed edge transition scheme. [ABSTRACT FROM PUBLISHER]

The concept presented in this paper proposes to exploit the structure of a 3-D slotted waveguide antenna array (SWAA) to turn it into a completely passive millimeter-wave identification (MMID) pressure sensor. The pressure sensor is realized by ending the SWAA with a metallic membrane, where the variation of pressure causes a variation in the radar cross section (RCS). The concept is studied across the RCS measurement of the SWAA ended by a sliding short circuit to emulate the membrane deflection. Experimental results show that a sensitivity of 22.46 mm2/mm of short-circuit displacement is reached at 57.8 GHz. An estimated read range of 1.1 m is considered with an MMID reader compliant with the ETSI European power emission regulation. [ABSTRACT FROM PUBLISHER]

This paper studies the detection of chipless frequency-coded tags. The detection exploits a temporal separation that allows obtaining the identification (ID) with only one measurement. In this way, the flexibility of reading of this type of chipless tags is clearly improved, which is highly expected for future real implementation. This temporal separation is possible when the tag presents a long-time signature, longer than the backscattering wave corresponding to the surrounding objects. A technique based on the short-time Fourier transform (STFT) is used to differentiate the useful parts of the signal, which contain the tag ID. Up to now, this was done by using a calibration process based on two measurements at least to remove coupling and clutter contribution. With the proposed approach the acquisition of the tag ID is direct, and it is not necessary to have further information such as the measurement of the environment without the tag. A study on the time duration of several frequency-coded tags is performed based on simulations and measurements. The study shows that this approach can be used with classical depolarizing chipless tags already proposed in the literature. It is proven that the proposed approach is useful to detect the tag response with a single measurement. [ABSTRACT FROM PUBLISHER]

This paper presents a complete radio frequency identification (RFID) test platform to characterize the nonlinear effects produced by passive ultra-high frequency (UHF) RFID chips. In full operation mode, automated measurements of activation power, harmonic response level, and impedances are performed in a wide frequency range up to the fourth harmonic. The characterization method, platform composition, and operation are explained through real measurements on UHF Class-1 Generation-2 chips. A harmonic treatment is presented thanks to the joint use of an RFID tester and impedance tuners, and the effect of the antenna-chip impedance matching on the harmonic responses is compared before and after treatment. To the best of our knowledge, no similar platform has been presented in the literature. [ABSTRACT FROM PUBLISHER]

In this paper, we demonstrate for the first time that a 19-bit chipless tag based on a paper substrate can be realized using the flexography technique, which is an industrial high-speed printing process. The chipless tag is able to operate within the ultra-wide band (UWB) and has a reasonable size (7\times 3 cm^2) compared to state-of-the-art versions. Thus, it is possible to use this design for various identification applications that require a low unit cost of tags. Both the simulation and measurement results are shown, and performance comparisons are provided between several realization processes, such as classical chemical etching, flexography printing, and catalyst inkjet printing. [ABSTRACT FROM PUBLISHER]

Entering ?RFID? on your Web browser will return you more than 50 million links. This huge number of references is a result of the impact of radio-frequency identification (RFID) technology worldwide [1]. Indeed, RFID technology is exploited in numerous domains, with thousands of applications, including more and more seen in everyday life. The RFID market is worth several billion dollars today, and its growth is more than 10% per year [2], [3]. There are two main classes of RFID devices. Figure 1 illustrates the main features of each class. The most known and broadly used class is the one based on the use of an integrated circuit (IC) chip in which the information is stored and that is connected to an antenna; the two together form the ?tag.? Such a technology exhibits several advantages, including flexibility and versatility in terms of the application. Nevertheless, it has some drawbacks mostly in terms of cost, robustness, reliability, data security, and poor recyclability of tags. More properties and new functionalities, such as sensing capabilities and tag-totag communication [4], are continually being developed, leading to the new paradigm of Internet of Things [5]. [ABSTRACT FROM PUBLISHER]

This paper presents a new radio frequency identification (RFID) chipless tag that is highly compact and potentially low-cost. This tag has a lot of advantages, such as being fully printable on products since no ground plane is needed for fabrication. The actual issue of the chipless tag family having a single layer, that is, their detuning effect, is compensated for the first time by a correction technique based on the use of a sensing resonator. The design is based on multiple \lambda/4 coplanar strip-line resonators where resonant frequencies can be shifted by setting an additional short circuit at particular locations. An accurate model is proposed to easily link the footprint of the structure to the resonant frequency. Considering a frequency resolution of 50 MHz for the reading system and a tag dimension of 15 \times \ 20 mm^2, 9 b can be encoded in the frequency band 2.0–5.5 GHz. Several experimental results validate the proposed design as well as its implementation in a realistic application and environment. [ABSTRACT FROM PUBLISHER]

This article presents a new chipless RFID tag operating in the frequency span 2 to 4 GHz. In particular the tag does not require any ground plane and it is made of 20 scatterers giving 20 b as coding capacity, for a compact size of 70\,\times\,25 mm^2, compatible with a credit-card format. Its fabrication process is potentially very cheap because it needs only one conductive layer, so that it can be fully printed directly on the product. To overcome the detuning effect inherent to a single layer tag and make this design robust to the environment versatility, a simple compensation technique is introduced and experimented for the first time. Measurements have been performed frequency domain, using amplitude and the group delay response. The exploitation of group delay appears to be very reliable and promising way to retrieve the coded information. [ABSTRACT FROM PUBLISHER]

A novel wireless sensor for the detection of food quality is presented. The main idea is to transform radio frequency identification (RFID) tags into RFID sensors, owing to a specific design of the tag antenna. From knowledge of the variation of the permittivity of food over time through experimental characterisation, it is possible to detect the time from which the food becomes improper for consumption based on the read‐range measurement of the designed sensing tags. This low‐cost ultra‐high frequency (UHF) RFID passive sensor was designed and experimentally tested on plastic‐film‐wrapped beef meat. The overall agreement between the experimental and simulation results shows the potential of this technique for real‐world applications in food traceability. [ABSTRACT FROM AUTHOR]