Special issue: Chipless RFID, an emerging technology

Vol. 68, n° 7-8, July-August 2013
Content available on Springerlink

Guest editors
Smaïl Tedjini, Université Grenoble-Alpes, France
Nemai Karmakar, Monash University, Australia


Smaïl Tedjini, Nemai Karmakar

Design rules for chipless RFID tags based ont multiple scatterers

Arnaud Vena, Etienne Perret and Smail Tedjini 

Grenoble-INP/LCIS, Valence, France

Abstract In this paper, we present some design rules to create a chipless RFID tag that encodes the information in the frequency domain. Some criterions are introduced to make the best choice concerning the elementary scatterers that act like signal processing antennas. The performance of several scatterers will be compared before a study on the radiating properties of a versatile C-like scatterer. An electrical model as well as a transfer function model is presented to best understand the frequency response of both a single-layer and a grounded scatterer. An example of the design and the optimization of a chipless RFID tag based on the use of multiple scatterers are provided, and the frequency optimization step for each resonant peak will be discussed.

Keywords RFID – Chipless RFID – Design rules – Signal processing antennas – Scatterers

IR-UWB-based chipless RFID system

Yizhu Shen1, Choi Look Law1, Sanming Hu2 and Jingjing Xia1

1 Nanyanag Technological University, Singapore
2 Agency for Science, Technology and Research (A*STAR), Singapore

Abstract This paper presents a chipless radio frequency identification (RFID) system, based on impulse radio ultra-wideband (IR-UWB) technology. This UWB-RFID system consists of a transmitter, a receiver, two tapered slot antennas, and several chipless tags. Covering the lower UWB frequency band in 3–5 GHz, the transmitter integrated circuit generates signals with high peak-to-peak amplitude of 6.6 V and short pulse duration of 1 ns. The receiver front end consists of amplifiers and filters, with total front-end gain up to 36 dB. This is followed by an equivalent time sampling analog to digital converter to sample the equivalent RF signals directly followed by digital signal processing in MATLAB. The tapered slot antenna has a high and relatively flat gain of 10 dBi. The chipless tag is uniplanar and with a size of 23 × 23 × 0.508 mm3 only. Based on these hardware designs developed in our research group, a novel method is proposed to separate two overlapped time-domain signals. This method, which is experimentally validated in this paper, greatly simplifies the hardware designs, especially the chipless tag. This chipless UWB-RFID system is an excellent candidate to realize a low-cost, low-power, and high-performance system for next-generation RFID applications.

Keywords Antenna mode – Backscattering – Impulse radio ultra-wideband (IR-UWB) – Chipless tag – Radio frequency identification (RFID) – Structural mode – UWB-RFID

Metamaterial-inspired passive chipless radio-frequency identification and wireless sensing

Christian Mandel, Bernd Kubina, Martin Schüßler and Rolf Jakoby

Technische Universität Darmstadt, Germany

Abstract The presented paper demonstrates how metamaterials with their unique properties and structures derived from metamaterials can offer solutions to overcome technical limitations of passive and chipless wireless sensor and RFID concepts. Basically, the metamaterial approach allows for miniaturization, higher sensitivity, and an extreme geometric flexibility. Miniaturization is certainly important for both, sensing and identification, while higher sensitivity is primarily applicable to sensors. The geometric flexibility is at first important for sensing since it allows for novel sensor concepts. But at least concerning buildup technology, also RFID concepts can benefit from this advantage. The presented examples of metamaterial-inspired passive chipless RFID and wireless sensing can be assigned to the following three categories: metamaterial resonator approaches, composite right/left-handed lines, and frequency-selective surfaces. In this paper, these different concepts are evaluated and discussed with regard to the metamaterial properties. Furthermore, criteria and figures of merit are given, which allow for a fair comparison of passive, chipless concepts and beyond. Finally, these criteria are applied to the presented sensor and identification concepts.
Keywords Chipless RFIDChipless wireless sensorsMetamaterial applications

Chipless RFID tags fabricated by fully printing of metallic inks

Botao Shao1,2, Qiang Chen1, Yasar Amin1, Ran Liu2 and Li-Rong Zheng1,2
1 KTH (Royal Institute of Technology), Stockholm, Sweden
2 Fudan University, Shanghai, China
Abstract This paper reviews recent advances in fully printed chipless radio frequency identification (RFID) technology with special concern on the discussion of coding theories, ID generating circuits, and tag antennas. Two types of chipless tags, one based on time-domain reflections and the other based on frequency domain signatures, are introduced. To enable a fully printed encoding circuit, linearly tapering technique is adopted in the first type of tags to cope with parasitic resistances of printed conductors. Both simulation and measurement efforts are made to verify the feasibility of the eight-bit fully printed paper-based tag. In the second type of tags, a group of LC tanks are exploited for encoding data in frequency domain with their resonances. The field measurements of the proof-of-concept of the tag produced by toner-transferring process and flexible printed circuit boards are provided to validate the practicability of the reconfigurable ten-bit chipless RFID tag. Furthermore, a novel RFID tag antenna design adopting linearly tapering technique is introduced. It shows 40 % save of conductive ink materials while keeping the same performance for conventional half-wave dipole antennas and meander line antennas. Finally, the paper discusses the future trends of chipless RFID tags in terms of fabrication cost, coding capacity, size, and reconfigurability. We see that, coupled with revolutionary design of low-cost tag antennas, fabrication/reconfiguration by printing techniques, moving to higher frequencies to shrink tag sizes and reduce manufacturing cost, as well as innovation in ID generating circuits to increase coding capacities, will be important research topics towards item-level tracking applications of chipless RFID tags.
Keywords Chipless RFID – Fully printing – Frequency resonance – LC tank – Linearly tapering – Paper substrate – Time-domain reflections

Identification tag in the terahertz frequency domain using low-cost and tunable refractive index materials

Maher Hamdi1, Frédéric Garet1, Lionel Duvillaret2, Philippe Martinez3 and Guy Eymin Petot Tourtollet3

1 Université de Savoie, France
2 KAPTEOS, Savoie Technolac, France
3 CTP, Domaine Universitaire, France
Abstract In the present paper, we propose a new structure of chipless and low-cost tag for data encoding in the terahertz frequency range. The device is based on a multilayer structure in which the thicknesses of the different layers are of the order of the wavelength, i.e., in the submillimeter range. In this device, the information is encoded in the volume of the tag thanks to the adjustable refractive index and low-cost materials, leading to a high level of security. The two main advantages compared to classical radiofrequency identification tags are the absence of metal and the encoding of the information in the volume of the structure, thus limiting the risk of damage during handling and preventing from reverse engineering, for example.

Keywords Chipless tag – Low cost – Multilayer structure – Tunable refractive index – Effective medium theory

Wireless sensing and identification based on radar cross section variability measurement of passive electromagnetic sensors

Hervé Aubert1, 2  , Franck Chebila1, 2, Mehdi Jatlaoui3, Trang Thai4, Hamida Hallil5, Anya Traille1, 2, Sofiene  Bouaziz1, 2, Ayoub Rifaï1, 2, Patrick Pons1, Philippe  Menini1, 2 and Manos Tentzeris4
1 LAAS-CNRS, Toulouse, France
2 University of Toulouse, UPS, INSA, INP, ISAE, France
3 IPDIA, Caen, France
4 Georgia Institute of Technology, Atlanta, GA 30332, USA
5 University of Bordeaux, France

Abstract In this paper, we present the wireless measurement of various physical quantities from the analysis of the radar cross section variability of passive electromagnetic sensors. The technique uses a millimeter frequency-modulated continuous-wave radar for both remote sensing and wireless identification of sensors. Long reading ranges (up to some decameters) are reached at the expense of poor measurement resolution (typically 10 %). A review of recent experimental results is reported for illustration purposes.
Keywords Wireless sensor network – Passive sensor – Remote sensing – Backscattering – Frequency modulation – FMCW radar – Millimeter wave – Chipless RFID

On the detection of chipless RFID through signal space representation

Prasanna Kalansuriya1, Nemai Chandra Karmakar and Emanuele Viterbo1 
1 Monash University, Clayton, Australia
Abstract This paper presents a novel approach to model and represent chipless radio-frequency identification (RFID) frequency signatures. The approach involves the geometrical representation of chipless RFID frequency signatures in a signal space. A small set of orthonormal basis functions is derived using singular value decomposition in order to represent the 2 b possible tag signatures of a b-bit chipless tag. Each tag signature is represented as a point in an L-dimensional signal space, and minimum distance detection is used to extract the information bit sequence of the tag. Detection error probability is also examined through analytical derivations and Monte Carlo simulation. A set of 3-bit tags were fabricated to validate the approach. Experimental results show that the new approach is capable of accurately detecting information contained in chipless RFID tags. This approach offers a solid mathematical framework for developing novel detection methods for chipless tags.

Keywords Chipless RFID – Spiral resonator – Signal space representation

Group delay modulation for pulse position coding based on periodically coupled C-sections

Raji Sasidharan Nair1, Etienne Perret1 and Smail Tedjini1
Grenoble-INP/LCIS, Valence, France
Abstract Chipless radio frequency identification (RFID) is an emerging research area nowadays. The recent development in this area proves its efficiency to compete with low cost identification systems like barcodes in the upcoming years. Chipless RFID encodes data using different kinds of spectral signature produced from some planar images as in the case of barcodes, the difference here is those images are made with conductive materials. Among the different ways of information encoding, a powerful way of encoding is time domain approach. This paper incorporates a tag using group delay encoding. The proposed chipless tag is composed of commensurate cascaded transmission line sections coupled at alternative ends (also known as C-sections). It consists of single group of C-sections. However, in order to increase the coding capacity, the proposed tag can allow multi-frequencies also. In addition to this, the tag is also compatible with commercial ultra wide band radar. The proposed tag is validated experimentally. It exhibits a good reading range of 1.2 m.
Keywords Time Domain tags – Chipless RFID – Group Delay – Backscattering – Encoding – UWB antennas

Detection and identification of objects based on radio-frequency signatures

Somnath Mukherjee
RB Technology, Milpitas,California, USA
Abstract Radio-frequency-based intelligent proximity sensors for detection as well as identification of objects were presented. A resonant structure is constructed that creates a near field with three-dimensional extent in the same order of magnitude as the physical size of the objects to be detected and identified. As an object is brought within the extent of the near field, a redistribution of electric and magnetic fields take place, modifying the reflection coefficient (i.e., impedance) of the resonant structure monitored through a port. The object under test, with its own natural frequencies, perturbs the resonant frequency of the monitoring structure to create a unique set of natural frequencies (poles and zeros). These poles and zeros, depending on the size, shape, material composition, and orientation, constitute the RF signature of the object and can be determined from the measurement of reflection coefficient. This technique can be used to create smart shelves for automated inventory without the need for tagging, as well for a variety of security applications. The technique can be used for metallic and non-metallic objects, as well as for a combination thereof. The basic principle is illustrated by way of electromagnetic simulation, and implementation of a smart tray using the principle is presented.

Keywords Intelligent proximity sensor – Radio-frequency identification – Object recognition – Object identification – Near-field communication – Impedance spectroscopy – Discrimination sensitivity – Smart shelf

Open Topics

Joint detection, channel estimation, and interference cancellation in downlink MC-CDMA communication systems using complex-valued multilayer neural networks

Hadi Mahdipour Hossein-Abad1, Hossein Nezamabadi-pour2, Dariush Abbasi-Moghadam2 and Morteza Khademi1
1 Ferdowsi University of Mashhad, Mashhad, Iran
2 Shahid Bahonar University, Kerman, Iran
Abstract Data detection in the presence of interference is one of the main challenges in multicarrier code division multiple access (MC-CDMA) communication systems. In this paper, a new detection technique for downlink MC-CDMA systems is proposed. This technique uses complex-valued multilayer neural networks at the receiver side. With the new definition for desired responses (±(1+J) instead of ±1, where J = -1), the convergence rate is increased (in the training process) regarding to saturation of imaginary output and the performance is increased because of increasing Euclidean distance of output neuron inputs in two states of desired outputs (with factor of 2). The performance of the proposed method is improved further by considering two various saturation coefficients (in the activation function of output layer) in the training and test processes. Since the last performance improving lead to low convergence rate, this effect is compensated by correcting the coefficient of training rate in the output layer. Simulation results confirm the high convergence rate, low computational complexity, and also good performance of the proposed method in wide range of SNRs.
Keywords Channel estimationInterference cancellationComplex-valued multilayer neural networksMC-CDMA communication systems

Diversity in cascaded N*Nakagami channels

P. M. Shankar
Department of Electrical & Computer Engineering, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104, USA
Abstract Short term fading conditions that are worse than those existing in typical Nakagami channels can be modeled using the cascaded approach where the received signal-to-noise ratio is treated as the product of N identical or nonidentical random variables that are either dependent or independent. Cascaded channels also permit the modeling of fading seen in amplify and forward relaying channels as well as keyhole channels. The simplest of these models, referred to as the N*Nakagami model, assumes that the received signal to noise ratio is the product of N independent and identically distributed gamma variables. The fading mitigation achieved in such cascaded channels through diversity is studied in this work. Through analytical approach and simulation, the performance of wireless channels is examined for the selection combining, equal gain combining, generalized selection combining, and maximal ratio combining algorithms. Results demonstrate the existence of severe degradations in cascaded fading channels and the comparative usefulness of the various algorithms in improving the data transmission capabilities. Even though the analysis was undertaken for the case of a coherent binary shift keying modem, results can easily be extended to other modems.
Keywords Cascaded channels Diversity Selection combining Maximal Ratio combining Equal Gain Combining Generalized Selection combining Error rates Outage probabilities