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RFID is taking the world by storm but lowering the price of the tag is a necessity in order to completely replace barcode systems with RFID systems. Researchers around the world have been working on chipless RFID systems. In this paper we present a novel chipless RFID system for barcode replacement. The system can be effectively used in conveyor belt applications. It uses spectral signatures to encoded data and hence provide a unique ID for every tagged object. The chipless tag is fully passive and planar.

Frequency signature chipless RFID tag based on spurline resonator is presented in this letter. Resonant response of spurline is explained by analyzing the surface current distribution. Chipless tag ...

The Global SAW Tag uses a recently-invented digital modulation based on simultaneous time position and phase shifting. A unique feature of this tag is that it satisfies global RFID requirements using the international 2.44 GHz ISM band. Precision amplitude and phase weighting of reflectors and accurate control of parasitic effects is critical to implementing this device. This tag has significantly more data bits, lower insertion loss, and smaller die area (i.e. lower cost) than previous SAW tags. These improvements eliminate the shortcomings that have previously limited the market for SAW RFID (radio frequency identification). A 2.44 GHz fundamental mode tag on 128/spl deg/ LiNbO/sub 3/ with 64-bit data capacity plus 16-bit error detection coding is described.

International audience; A high-level (i.e., in terms of security) authentication method is proposed in this paper, where the chipless radio frequency identification (RFID) is extended to the chipless authentication. The proposed method is based on low cost inkjet-printed square check patterned chipless tags, whose design is explicitly optimized keeping the randomness inherent to the inkjet printing process in view. These optimized chipless tags are very difficult to duplicate, as their unique backscattered electromagnetic (EM) responses depend on the proximate coupling among the possible separated squares, which is happened naturally due to the randomness in inkjet printing. The performance of the proposed method is analyzed by a low cost impulse radio (IR) ultrawideband (UWB) chipless RFID reader as well as by the highly accurate vector network analyzer (VNA) based chipless RFID reader. The achieved probability of error is comparable to the various fingerprint evaluation campaigns found in the literature.

NASA is investigating passive wireless sensor technology to reduce instrumentation mass and volume in ground testing, air flight, and space exploration applications. Vehicle health monitoring systems (VHMS) are desired on all aerospace programs to ensure the safety of the crew and the vehicles. Pervasive passive wireless sensor networks facilitate VHMS on aerospace vehicles. Future wireless sensor networks on board aerospace vehicles will be heterogeneous and will require active and passive network systems. Since much has been published on active wireless sensor networks, this work will focus on the need for passive wireless sensor networks on aerospace vehicles. Several passive wireless technologies such as microelectromechanical systems MEMS, SAW, backscatter, and chipless RFID techniques, have all shown potential to meet the pervasive sensing needs for aerospace VHMS applications. A SAW VHMS application will be presented. In addition, application areas including ground testing, hypersonic aircraft and spacecraft will be explored along with some of the harsh environments found in aerospace applications.

This paper focuses on the frequency coded chipless Radio Frequency Identification (RFID) wherein the tag’s information bits are physically encoded by the resonators’ notch position which has an effect on the frequency spectrum of the backscattered or retransmitted signal of the tag. In this regard, the notch analytical model is developed to consider the notch position and quality factor. Besides, the radar cross section (RCS) mathematical representation of the tag is introduced to consider the incident wave’s polarization and orientation angles. Hence, the influences of the incident wave’s orientation and polarization mismatches on the detection performance are quantified. After that, the tag measurement errors and limitations are comprehensively explained. Therefore, approaches to measureing RCS- and retransmission-based tags are introduced. Furthermore, the maximum reading range is theoretically calculated and practically verified considering the Federal Communications Commission (FCC) Ultra Wideband (UWB) regulations. In all simulations and experiments conducted, a mono-static configuration is considered, in which one antenna is utilized for transmission and reception.

International audience; A simple and convenient approach for the calibration of cross polarized radar cross section (RCS) is presented. We have shown that a planar depolarizing chipless radio frequency identification (RFID) tag can be utilized as a reference calibration target for the calibration, especially for the characterization of its counterpart depolarizing chipless RFID tags. To prove the concept, one chipless RFID tag is used as a reference calibration tag and another one as a test tag. The designs of chipless RFID tags are based on RF encoding particle (REP) and taken from the literature. The experimental performance of the proposed method is compared with the ideal simulated RCS. The worst calibration error over a frequency range from 4 to 7 GHz is less than 3.11 dB, whereas the worst calibration error over a frequency range from 4 to 6 GHz is less than 2.51 dB.

This paper studies the implementation of an RFID chipless sensor based on split ring resonators. It operates in the ISM band at 2.45GHz to detect a change of carbon dioxide, and a variation of temperature. The realization of this passive wireless sensor involves inkjet printing using several ink types so that a device that works can be realized from scratch in a few stages. The substrates used are flexible materials to allow for seamless integration on any object shapes. Several samples have been printed on polyimide substrate 50 µm thick to validate the design with the help of wireless measurements. Finally, another set of samples printed on an ordinary cardboard of 550 µm thickness is realized and measured, and the performance achieved are compared with those of the polyimide based sensors.

A novel approach to decode information in a chipless RFID tag using signal space representation (SSR) is presented. SSR represents 2^b possible tag signatures of a b-bit tag as linear combinations of a small set of $L$ orthonormal basis functions. Each signature encoding a binary bit sequence is represented by a point in an $L$-dimensional constellation. Prototype 3-bit chipless RFID tags are used to validate the detection technique. The proposed method gives a solid mathematical framework to develop detection and decoding methods for more complicated tag reading scenarios.

This paper presents the design of a sewed chipless RFID tag and sensor, on a fabric for wearable applications. The proposed design is based on three sewn scatterers on cotton textile. The tag is realized using a computer-aided sewing machine and electro-thread plated with silver. The simulation and frequency-domain measurement results validate the design from 3 to 6 GHz. The tag's static backscattered response can be identified in free space and on the human body. Some preliminary results from a sewn stretchable sensor are also given to demonstrate the potential for biomedical applications. Finally, we discuss the main challenges concerning the practical implementation of this technology.

Chipped radio-frequency identification (RFID) sensor systems have been studied for structural health monitoring (SHM) applications. However, the use of chip in sensor tags and its standardized narrowband operation contribute shortcomings in cost, durability, and detection capability. This paper presents a novel use of the frequency signature-based chipless RFID for metal crack detection and characterization operating in ultra-wideband frequency. The vision is to implement a low-cost and high-temperature-resistant passive wireless sensor able to monitor the crack on a metallic structure with multiparameter detection. We propose a chipless RFID sensor tag integrating four tip-loaded dipole resonators as a 4-bit ID encoder and a circular microstrip patch antenna (CMPA) resonator as a crack sensor. The radar cross section spectrum of the chipless RFID sensor tag generates four resonant frequencies from the dipole resonators and a resonant frequency from the CMPA resonator. Simulation and experimental results show that the resonant frequency shift of the CMPA is a useful feature to indicate the crack orientation and the crack width on a metallic structure. The direction of the resonant frequency shift represents the orientation of the crack, while the magnitude of the resonant frequency shift is proportional to the width of the crack. Furthermore, the experimentation with a natural fatigue crack sample proves that the proposed sensor tag is capable of detecting submillimeter cracks.

Electromagnetic encoders exclusively made of a dielectric material are presented in this paper. The proposed encoders consist of a grid (chain) of apertures, which can be arranged circularly (rotary encoders) or linearly (linear encoders) on the considered substrate, a dielectric material. Such encoders can be useful for the measurement of angular or linear displacements and velocities based on pulse counting (similar to optical encoders). Alternatively, the encoder can be used as a near-field chipless-RFID tag based on the presence or absence of apertures at predefined positions in the chain (hence providing an identification code). In both applications, encoder reading is based on the detection of the apertures (pulses) as the encoder moves on top of a dedicated sensing element (reader). In this work, the reader is a microstrip line loaded with a complementary spiral resonator (CSR) etched in the ground plane, and encoder reading is based on the variation of the transmission coefficient caused by encoder motion. Specifically, the notch generated by the CSR shifts up each time an aperture lies on top of the CSR (due to permittivity variation). Thus, the apertures can be detected from the amplitude modulated (AM) signal generated at the output port of the CSR-loaded line, when it is fed by a properly tuned harmonic (interrogation) signal. The main originality of the work is the working principle for encoder reading (permittivity contrast), as well as the lack of metallic elements in the encoder (representing a reduction in fabrication costs).

Aim of this paper is to design a fundamental building block of a spectral domain chipless RFID system based on cross-polar scattering. A novel chipless tag able to provide multi-frequency polarization conversion is proposed. The tag is able to convert the polarization of impinging electromagnetic fields at multiple frequencies guaranteeing good polarization conversion both for vertical, horizontal and oblique azimuthal incidence without introducing additional unwanted high-order resonances. The use of such tags allows a very low-cost tagging of very large metallic platforms regardless of their dimensions and their huge echo.

A chipless RF identifiction (RFID) sensor system platform consisting of passive chipless RFID sensor tags and specialized reader has been developed for cyber centric monitoring applications. The sensor tags are fabricated on a flexible substrate, and the tag identification (ID) generation circuit consists of microstrip transmission lines. Two tag configurations are presented. The first configuration (conf-I) consists of an antenna and an integrated sensor. The second configuration (conf-II) consists of an antenna, ID generation circuit, and a sensor. The specialized reader system, consisting of an analog reader section and an on-board computer system, communicates with the sensor tags using load modulated backscattered communication techniques, at 915-MHz carrier signal. The reader, receiving the ID code generated by a tag, constructs it into a standardized RFID data frame, suitable for cyberspace information exchange. The developed system has been tested for wireless monitoring of ethylene gas. Using a conf-I tag, demodulated voltage change of 3.05 mV is observed at the reader, when the ethylene gas concentration changes from 0 to 100 ppm. The presented conf-II tag prototype allows generation of eight different ID codes and an average of 26.51deg/pF phase change in the backscattered signal, when the load capacitance (sensor) of the tag changes between 1-5 pF.

In this paper, we focus on the chipless radio-frequency identification (RFID), where the tag information bits are encoded by the peak/notch pattern appeared in the frequency spectrum of the radar cross section (RCS) of the tag. In particular, we restrict our attention to a simple yet prevalent “binary” coding method, where a bit 0 or bit 1 is encoded by the absence or presence of the peak/notch, respectively. We provide an information-theoretic framework for the tag identification based on such a binary coding method. Our aim is to accommodate more bits in the limited bandwidth without degrading the identification performance. To this end, we first formulate the detection of each bit as a binary asymmetric channel (where a signal processing approach is integrated into each interrogation to enhance the underlying channel quality). Moreover, it is proposed to perform multiple interrogations with majority rule-based detection (in correspondence to the signal processing approach in each interrogation). Furthermore, we introduce some error-detecting codes to further improve the performance of tag identification. For instance, motivated by the asymmetric property of the channel model, we propose to apply the constant weight code and the Berger–Freiman code (as two representatives of non-systematic and systematic codes, respectively) to the problem to be addressed in this paper. In addition, an investigation is also conducted into the cyclic redundancy check (CRC) codes (as a representative of those codes that are not dedicated to the binary asymmetric channel but could be potentially competitive for error detection). The system’s performance is analyzed through the key parameters, namely the successful transmission rate, the false identification rate (i.e., the probability of undetected errors), and the expected number of retransmissions/interrogations. The effectiveness of the proposed methods is demonstrated by the numerical results.

In this paper novel semi-platform tolerant 20-bits chipless RFID tag based on array of dipoles closely coupled to metallic plate of the size 60 × 60 mm is presented. Quality factor of single dipole-plate is analysed to better understand the resonant behavior of the scatterer. RCS response level about 15 dBsm, spectral bit capacity > 15 bit/GHz and good frequency and amplitude stability of the RCS represent promising solution for chipless RFID systems.

RFID technology is taking the world by storm and there is a requirement for having cheap RFID tags. Chipless transponders offer cheap solutions which can compare with the barcode. We present two types of frequency signature based RFID transponders using multiresonators and fractal antennas. In this article we present the novel chipless RFID concept and simulated and measured results of the chipless tags.