Chipless RFID

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Chipless RFID tags are RFID tags that do not require a microchip in the transponder.

Contents

RFIDs offer longer range and ability to be automated, unlike barcodes that require a human operator for interrogation. The main challenge to their adoption is the cost of RFIDs. The design and fabrication of ASICs needed for RFID are the major component of their cost, so removing ICs altogether can significantly reduce its cost. The major challenges in designing chipless RFID is data encoding and transmission. [1]

Development of chipless RFID tags

Chipless tag printed with inkjet printing conductive ink. Chipless tag.jpg
Chipless tag printed with inkjet printing conductive ink.

To understand the development of chipless RFID tags, it is important to view it in comparison to classic RFID and barcode. RFID benefits from a very wide spectrum of functionalities, related to the use of radio-frequency (RF) waves for data exchange. The acquisition of the identifier (ID) is made much easier and volumetric readings are possible, all on tags containing modifiable information. These functions are impossible to implement with a barcode, but in reality, 70% of the items manufactured worldwide are equipped with it. The reasons for this enthusiasm are simple: barcode functions very well and is extremely cheap, the label as well as the reader. This is why barcodes remain the uncontested benchmark in terms of identification, with a cost-to-simplicity-of-use ratio that remains unequalled.

It is also true that RFID contributes other significant functionalities, and the question is therefore one of imagining a technology based on RF waves as a communication vector that would retain some of the advantages of barcodes. Pragmatically speaking, the question of system cost, and particularly of the tags that must be produced in large numbers, remains the central point. Due to the presence of electronic circuits, these tags have a non-negligible cost that is a very great deal higher than that of barcodes. It is logical therefore that a simple solution consists of producing chipless RF tags. The high cost of RFID tags is actually one of the principal reasons that chipped RFID is rare in the market for tags for widely distributed products, a market that numbers in the tens of thousands of billions of units sold per year. In this market, optic barcodes are very widely used.

However, technically speaking, chipped RFID offers significant advantages including increased reading distance and the ability to detect a target outside the field of vision, whatever its position. The concept of chipless RF label has been developed with the idea of competing with barcodes in certain areas of application. RFID has many arguments in its favor in terms of functionality, the only problem remaining being the price. The barcode offers no other feature than the ID recovery; however, the technology is time-tasted, widespread, and extremely low cost.

Chipless RFID has also good arguments in terms of functionality. Some functionalities are degraded versions of what RFID can do (read range / reading flexibility are reduced ...), others seem to be even more relevant in chipless (discretion, product integrity of the tag). The main advantage is the cost of chipless tags. As compared to the barcodes, the chipless technology must bring other features that are impossible to implement with the optical approach, while remaining a very low cost approach, that is to say, a potentially printable one. This is why the writing / rewriting and sensor capabilities are crucial features for the large-scale development of such a technology. For instance, the development of very low cost sensor - tags is now eagerly awaited for, for application reasons. [2]

Operating principle

Chipless rfid operating principle. A. Vena, E. Perret, and S. Tedjini, 2013. Chipless RFID Operating Principle.png
Chipless rfid operating principle. A. Vena, E. Perret, and S. Tedjini, 2013.

Like various existing RFID technologies, chipless RFID tags are associated with a specific RF reader, which questions the tag and recovers the information contained in it. The operating principle of the reader is based on the emission of a specific electromagnetic (EM) signal toward the tag, and the capture of the signal reflected by the tag. The processing of the signal received—notably via a decoding stage—makes it possible to recover the information contained in the tag. [3]

However, chipless RFID tags are fundamentally different from RFID tags. In the latter, a specific frame is sent by the reader [4] toward the tag according to a classic binary modulation schema. The tag demodulates this signal, processes the request, possibly writes data in its memory, and sends back a response, modulating its load. [5] Chipless RFID tags, on the other hand, function without a communication protocol. They employ a grid of dipole antennas that are tuned to different frequencies. The interrogator generates a frequency sweep signal and scans for signal dips. Each dipole antenna can encode one bit. The frequency swept will be determined by the antenna length. They can be viewed as radar targets possessing a specific, stationary temporal or frequential signature. With this technology, the remote reading of an identifier consists of analyzing the radar signature of the tag.

Currently, one of main challenges of the chipless technology is the robustness of tag detection in different environments. It is useless to try to increase the quantity of information that a chipless tag can have if the tag ID cannot be read properly in real environments and without complex calibration techniques. The detection of a chipless tag in noisy environments is much more difficult in chipless than in UHF RFID due to the absence of modulation in time, that is, the absence of two different states in the backscattering signal.

Chemical-based

Self-generating ceramic mixtures

In 2001, Roke Manor Research centre announced materials that emit characteristic radiation when moved. These may be exploited for storage of a few data bits encoded in the presence or absence of certain chemicals. [6]

Biocompatible ink

Somark employed a dielectric barcode that may be read using microwaves. The dielectric material reflects, transmits and scatters the incident radiation; the different position and orientation of these bars affects the incident radiation differently and thus encodes the spatial arrangement in the reflected wave. The dielectric material may be dispersed in a fluid to create a dielectric ink. [7] They were mainly used as tags for cattle, which were "painted" using a special needle. The ink may be visible or invisible according to the nature of the dielectric, Operating frequency of the tag may be changed by using different dielectrics. [8]

CrossID nanometric ink

This system uses varying magnetism. Materials resonate at different frequencies when excited by radiation. The reader analyzes the spectrum of the reflected signal to identify the materials. 70 different materials were found. Each material's presence or absence may be used to encode a bit, enabling encoding up to 270 unique binary strings. They work on frequencies between three and ten gigahertz. [9]

Passive antenna

In 2004, Tapemark announced a chipless RFID that will have only a passive antenna with a diameter as small as 5  µm. The antenna consists of small fibers called nano-resonant structures. Spatial difference in structure encode data. The interrogator sends out a coherent pulse and reads back an interference pattern that it decodes to identify a tag. They work from 24 GHz–60 GHz. [10] Tapemark later discontinued this technology.

Magnetism-based

Programmable magnetic resonance

Sagentia's devices are acousto-magnetic. They exploit the resonance features of magnetically soft magnetostrictive materials and the data retention capability of hard magnetic materials. Data is written to the card using the contact method. The resonance of the magnetostrictive material is altered by the data stored in the hard material. Harmonics may be enabled or disabled corresponding to the state of the hard material, thus encoding the device state as a spectral signature. Tags built by Sagentia for AstraZeneca fall into this category. [11] [12] [13]

Magnetic data tagging

Flying Null technology uses a series of passive magnetic structures, much like the lines used in conventional barcodes. These structures are made of soft magnetic material. The interrogator contains two permanent magnets with like poles. The resulting magnetic field has a null volume in the centre. Additionally, interrogating radiation is used. The magnetic field created by the interrogator is such that it drives the soft material to saturation except when it is at the null volume. When in the null volume the soft magnet interacts with the interrogating radiation thus giving away the position of the soft material. Spatial resolution of more than 50 μm may be attained. [14] [15]

Surface acoustic wave

Illustration of a simple SAW RFID encoding 013 in base 4. The first and last reflectors are used for calibration. The second and second last for error detection. The data is encoded in the remaining three groups. Each group contains 4 slots and an empty slot followed by another group. SAW RFID.png
Illustration of a simple SAW RFID encoding 013 in base 4. The first and last reflectors are used for calibration. The second and second last for error detection. The data is encoded in the remaining three groups. Each group contains 4 slots and an empty slot followed by another group.

Surface acoustic wave devices consists of a piezoelectric crystal-like lithium niobate on which transducers are made by single-metal-layer photolithographic technology. The transducers usually are Inter-Digital Transducers (IDT), which have a two-toothed comb-like structure. An antenna is attached to the IDT for reception and transmission. The transducers convert the incident radio wave to surface acoustic waves that travel on the crystal surface until it reaches the encoding reflectors that reflect some waves and transmit the rest. The IDT collects the reflected waves and transmits them to the reader. The first and last reflectors are used for calibration as the response may be affected by physical parameters such as temperature. A pair of reflectors may also be used for error correction. The reflections increase in size from nearest to farthest of the IDT to account for losses due to preceding reflectors and wave attenuation. Data is encoded using Pulse Position Modulation (PPM). The crystal is logically divided into groups, such that each group typically has a length equal to the inverse of the bandwidth. Each group is divided into slots of equal width. The reflector may be placed in any slot. The last slot in each group is usually unused, leaving n-1 positions for the reflector, thus encoding n-1 states. The repetition rate of the PPM is equal to the system bandwidth. The reflector's slot position may be used to encode phase. The devices' temperature dependence means they can also act as temperature sensors. [16]

Capacitively tuned split microstrip resonators

They employ a grid of dipole antennas that are tuned to different frequencies. The interrogator generates a frequency sweep signal and scans for signal dips. Each dipole antenna can encode one bit. The frequency swept will be determined by the antenna length. [17]

Paper chipless tag printed with flexography technique. Paper chipless tag.jpg
Paper chipless tag printed with flexography technique.

Many improvements have been done in the past few years on communication systems, based on electronic devices where an integrated circuit is at the heart of the whole system. The democratization of these chipped based systems like the RFID one have however given rise to environmental issues.

Lately, new research projects, such as European Research Council (ERC) funded project ScattererID, [18] have introduced the paradigm of RF communication system based on chipless labels, where new useful functionalities can be added. With comparable costs to a barcode, these labels should stand out by providing more functionalities than the optical approach. The objective of ScattererID project is to show that it is possible to associate the chipless label ID with other features like the ability to write and rewrite the information, to associate an ID with a sensor function and to associate an ID with gesture recognition.

The possibility of designing reconfigurable and low cost tags involves the development of original approaches at the forefront of progress, like the use of CBRAM from microelectronics, allowing to achieve reconfigurable elements based on Nano-switches.

Related Research Articles

<span class="mw-page-title-main">Microwave</span> Electromagnetic radiation with wavelengths from 1 m to 1 mm

Microwave is a form of electromagnetic radiation with wavelengths ranging from about 30 centimeters to one millimeter corresponding to frequencies between 1000 MHz and 300 GHz respectively. Different sources define different frequency ranges as microwaves; the above broad definition includes UHF, SHF and EHF bands. A more common definition in radio-frequency engineering is the range between 1 and 100 GHz. In all cases, microwaves include the entire SHF band at minimum. Frequencies in the microwave range are often referred to by their IEEE radar band designations: S, C, X, Ku, K, or Ka band, or by similar NATO or EU designations.

Radio-frequency identification (RFID) uses electromagnetic fields to automatically identify and track tags attached to objects. An RFID system consists of a tiny radio transponder, a radio receiver and transmitter. When triggered by an electromagnetic interrogation pulse from a nearby RFID reader device, the tag transmits digital data, usually an identifying inventory number, back to the reader. This number can be used to track inventory goods.

<span class="mw-page-title-main">Antenna (radio)</span> Electrical device

In radio engineering, an antenna or aerial is the interface between radio waves propagating through space and electric currents moving in metal conductors, used with a transmitter or receiver. In transmission, a radio transmitter supplies an electric current to the antenna's terminals, and the antenna radiates the energy from the current as electromagnetic waves. In reception, an antenna intercepts some of the power of a radio wave in order to produce an electric current at its terminals, that is applied to a receiver to be amplified. Antennas are essential components of all radio equipment.

<span class="mw-page-title-main">Parabolic antenna</span> Type of antenna

A parabolic antenna is an antenna that uses a parabolic reflector, a curved surface with the cross-sectional shape of a parabola, to direct the radio waves. The most common form is shaped like a dish and is popularly called a dish antenna or parabolic dish. The main advantage of a parabolic antenna is that it has high directivity. It functions similarly to a searchlight or flashlight reflector to direct radio waves in a narrow beam, or receive radio waves from one particular direction only. Parabolic antennas have some of the highest gains, meaning that they can produce the narrowest beamwidths, of any antenna type. In order to achieve narrow beamwidths, the parabolic reflector must be much larger than the wavelength of the radio waves used, so parabolic antennas are used in the high frequency part of the radio spectrum, at UHF and microwave (SHF) frequencies, at which the wavelengths are small enough that conveniently-sized reflectors can be used.

This is an index of articles relating to electronics and electricity or natural electricity and things that run on electricity and things that use or conduct electricity.

<span class="mw-page-title-main">Resonator</span> Device or system that exhibits resonance

A resonator is a device or system that exhibits resonance or resonant behavior. That is, it naturally oscillates with greater amplitude at some frequencies, called resonant frequencies, than at other frequencies. The oscillations in a resonator can be either electromagnetic or mechanical. Resonators are used to either generate waves of specific frequencies or to select specific frequencies from a signal. Musical instruments use acoustic resonators that produce sound waves of specific tones. Another example is quartz crystals used in electronic devices such as radio transmitters and quartz watches to produce oscillations of very precise frequency.

Automatic identification and data capture (AIDC) refers to the methods of automatically identifying objects, collecting data about them, and entering them directly into computer systems, without human involvement. Technologies typically considered as part of AIDC include QR codes, bar codes, radio frequency identification (RFID), biometrics, magnetic stripes, optical character recognition (OCR), smart cards, and voice recognition. AIDC is also commonly referred to as "Automatic Identification", "Auto-ID" and "Automatic Data Capture".

Electronic article surveillance (EAS) is a type of system used to prevent shoplifting from retail stores, pilferage of books from libraries, or unwanted removal of properties from office buildings. EAS systems typically consist of two components: EAS antennas and EAS tags or labels. EAS tags are attached to merchandise; these tags can only be removed or deactivated by employees when the item is properly purchased or checked out. If merchandise bearing an active tag passes by an antenna installed at an entrance/exit, an alarm sounds alerting staff that unauthorized merchandise is leaving the store. Some stores also have antennas at entrances to restrooms to deter shoppers from taking unpaid-for merchandise into the restroom where they could remove the tags.

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Dielectric heating, also known as electronic heating, radio frequency heating, and high-frequency heating, is the process in which a radio frequency (RF) alternating electric field, or radio wave or microwave electromagnetic radiation heats a dielectric material. At higher frequencies, this heating is caused by molecular dipole rotation within the dielectric.

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Smart Label, also called Smart Tag, is an extremely flat configured transponder under a conventional print-coded label, which includes chip, antenna and bonding wires as a so-called inlay. The labels, made of paper, fabric or plastics, are prepared as a paper roll with the inlays laminated between the rolled carrier and the label media for use in specially-designed printer units.

ISO/IEC 18000-3 is an international standard for passive RFID item level identification and describes the parameters for air interface communications at 13.56 MHz. The target markets for MODE 2 are in tagging systems for manufacturing, logistics, retail, transport and airline baggage. MODE 2 is especially suitable for high speed bulk conveyor fed applications.

<span class="mw-page-title-main">Metamaterial antenna</span>

Metamaterial antennas are a class of antennas which use metamaterials to increase performance of miniaturized antenna systems. Their purpose, as with any electromagnetic antenna, is to launch energy into free space. However, this class of antenna incorporates metamaterials, which are materials engineered with novel, often microscopic, structures to produce unusual physical properties. Antenna designs incorporating metamaterials can step-up the antenna's radiated power.

RFID on metal are radio-frequency identification (RFID) tags which perform a specific function when attached to metal objects. The ROM tags overcome some of the problems traditional RFID tags suffer when near metal, such as detuning and reflecting of the RFID signal, which can cause poor tag read range, phantom reads, or no read signal at all.

Fresnel zone antennas are antennas that focus the signal by using the phase shifting property of the antenna surface or its shape . There are several types of Fresnel zone antennas, namely, Fresnel zone plate, offset Fresnel zone plate antennas, phase correcting reflective array or "Reflectarray" antennas and 3 Dimensional Fresnel antennas. They are a class of diffractive antennas and have been used from radio frequencies to X rays.

The IEEE 1902.1-2009 standard is a wireless data communication protocol also known as RuBee, operates within the Low Frequency radio wave range of 30–900 kHz. Although very resistant to interference, metal, water and obstacles, it is very limited in range, usually only suitable for short-range networks. The baud rate is limited to 1,200 kB/s, making it a very low-rate communication network as well. This standard is aimed at the conception of wireless network of sensors and actuators in industrial and military environments. One of the major advantage 1902.1 tags is they are extremely low power and last for years on a simple coin size battery and they can be sealed in a MIL STD 810G package. RuBee tags emit virtually no RF and do not produce any Compromising Emanations, as a result are used in high security facilities. RuBee tags are safe and in use near and on high explosive facilities.

In radio systems, many different antenna types are used whose properties are especially crafted for particular applications. Antennas can be classified in various ways. The list below groups together antennas under common operating principles, following the way antennas are classified in many engineering textbooks.

References

  1. Radio Frequency Identification and Sensors: From RFID to Chipless RFID, Etienne Perret, Wiley-ISTE, 2014
  2. La RFID sans puce - Théorie, conception, mesures, Arnaud Vena, Etienne Perret, Smail Tedjini, ISTE, 2016
  3. RCS Synthesis for Chipless RFID - Theory and Design, Olivier Rance, Etienne Perret, Romain Siragusa, Pierre Lemaitre-Auger, ISTE-Elsevier Jul. 2017
  4. Chipless RFID Reader Design for Ultra-Wideband Technology, Marco Garbati, Etienne Perret, Romain Siragusa, ISTE-Elsevier, Fev. 2018.
  5. Chipless RFID based on RF Encoding Particle - Realization, Coding and Reading System, Arnaud Vena, Etienne Perret, Smail Tedjini, ISTE-Elsevier, Aug. 2016.
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  9. "Firewall Protection for Paper Documents". RFID Journal. Retrieved 17 August 2013.
  10. "RFID Fibers for Secure Applications". RFID Journal. 26 March 2004. Retrieved 17 August 2013.
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  12. "Acousto-magnetic System". How Stuff Works. April 2000. Retrieved 16 August 2013.
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  14. Crossfield, M. (1 January 2001). "Have null, will fly". IEE Review. 47 (1): 31–34. doi:10.1049/ir:20010111.
  15. "The Use of Flying Null Technology in the Tracking of Labware in Laboratory Automation". JALA. Retrieved 17 August 2013.
  16. Plessky, VP; Reindl, LM (March 2010). "Review on SAW RFID tags". IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control. 57 (3): 654–68. doi:10.1109/tuffc.2010.1462. PMID   20211785. S2CID   1237156.
  17. Jalaly, I.; Robertson, I.D. (2005). "Capacitively-tuned split microstrip resonators for RFID barcodes". 2005 European Microwave Conference. Vol. 2. pp. 4 pp.–1164. doi:10.1109/EUMC.2005.1610138. ISBN   978-2-9600551-2-2. S2CID   31536974.
  18. ScattererID Analysis and synthesis of wideband scattered signals from finite-size targets – aspect-independent RF analog footprint, Etienne Perret, 2018.