Radio-frequency identification
An RFID tag.
Radio-frequency identification (RFID) is an automatic identification method, relying on storing and remotely retrieving data using devices called RFID tags or transponders.
An RFID tag is an object that can be applied to or incorporated into a product, animal, or person for the purpose of identification using radiowaves. Some tags can be read from several meters away and beyond the line of sight of the reader.
Most RFID tags contain at least two parts. One is an integrated circuit for storing and processing information, modulating and demodulating a (RF) signal and can also be used for other specialized functions. The second is an antenna for receiving and transmitting the signal. A technology called chipless RFID allows for discrete identification of tags without an integrated circuit, thereby allowing tags to be printed directly onto assets at lower cost than traditional tags.
Today, a significant thrust in RFID use is in enterprise supply chain management, improving the efficiency of inventory tracking and management. However, a threat is looming that the current growth and adoption in enterprise supply chain market will not be sustainable. A fair cost-sharing mechanism, rational motives and justified returns from RFID technology investments are the key ingredients to achieve long-term and sustainable RFID technology adoption .
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History of RFID tag
Mario Cardullo's in 1973 was the first true ancestor of modern RFID; a passive radio transponder with memory. The initial device was passive, powered by the interrogating signal, and was demonstrated in 1971 to the New York Port Authority and other potential users and consisted of a transponder with 16 bit memory for use as a toll device. The basic Cardullo patent covers the use of RF, sound and light as transmission medium. The original business plan presented to investors in 1969 showed uses in transportation (automotive vehicle identification, automatic toll system, electronic license plate, electronic manifest, vehicle routing, vehicle performance monitoring), banking (electronic check book, electronic credit card), security (personnel identification, automatic gates, surveillance) and medical (identification, patient history).
A very early demonstration of reflected power (modulated backscatter) RFID tags, both passive and semi-passive, was done by Steven Depp, Alfred Koelle and Robert Freyman at the Los Alamos Scientific Laboratory in 1973. The portable system operated at 915 MHz and used 12 bit tags. This technique is used by the majority of today's UHF and microwave RFID tags..
RFID tags
RFID tags come in three general varieties: passive, active, or semi-passive (also known as battery-assisted). Passive tags require no internal power source, thus being pure passive devices (they are only active when a reader is nearby to power them), whereas semi-passive and active tags require a power source, usually a small battery.
RFID backscatter
To communicate, tags respond to queries generating signals that must not create interference with the readers, as arriving signals can be very weak and must be told apart. Besides backscattering, load modulation techniques can be used to manipulate the reader's field. Typically, backscatter is used in the far field, whereas load modulation applies in the nearfield, within a few wavelengths from the reader.
Passive
Passive RFID tags have no internal power supply. The minute electrical current induced in the antenna by the incoming radio frequency signal provides just enough power for the CMOS integrated circuit in the tag to power up and transmit a response. Most passive tags signal by backscattering the carrier wave from the reader. This means that the antenna has to be designed to both collect power from the incoming signal and also to transmit the outbound backscatter signal. The response of a passive RFID tag is not necessarily just an ID number; the tag chip can contain non-volatile, possibly writable EEPROM for storing data.
Passive tags have practical read distances ranging from about 10 cm (ISO 14443) up to a few meters (Electronic Product Code (EPC) and ISO 18000-6), depending on the chosen radio frequency and antenna design/size. Due to their simplicity in design they are also suitable for manufacture with a printing process for the antennas. The lack of an onboard power supply means that the device can be quite small: commercially available products exist that can be embedded in a sticker, or under the skin in the case of low frequency RFID tags.
Active
Unlike passive RFID tags, active RFID tags have their own internal power source, which is used to power the integrated circuits and broadcast the signal to the reader. Active tags are typically much more reliable (i.e. fewer errors) than passive tags due to the ability for active tags to conduct a "session" with a reader. Active tags, due to their onboard power supply, also transmit at higher power levels than passive tags, allowing them to be more effective in "RF challenged" environments like water (including humans/cattle, which are mostly water), metal (shipping containers, vehicles), or at longer distances, generating strong responses from weak requests (as opposed to passive tags, which work the other way around). In turn, they are generally bigger and more expensive to manufacture, and their potential shelf life is much shorter.
Many active tags today have practical ranges of hundreds of meters, and a battery life of up to 10 years. Some active RFID tags include sensors such as temperature logging which have been used to monitor the temperature of perishable goods like fresh produce or certain pharmaceutical products. Other sensors that have been married with active RFID include humidity, shock/vibration, light, radiation, temperature, and atmospherics like ethylene. Active tags typically have much longer range (approximately 500 m/1500 feet) and larger memories than passive tags, as well as the ability to store additional information sent by the transceiver. The United States Department of Defense has successfully used active tags to reduce logistics costs and improve supply chain visibility for more than 15 years.
Semi-passive
Semi-passive tags are similar to active tags in that they have their own power source, but the battery only powers the microchip and does not broadcast a signal. The RF energy is reflected back to the reader like a passive tag. An alternative use for the battery is to store energy from the reader to emit a response in the future, usually by means of backscattering.
The battery-assisted receive circuitry of semi-passive tags lead to greater sensitivity than passive tags, typically 100 times more. The enhanced sensitivity can be leveraged as increased range (by a factor 10) and/or as enhanced read reliability (by one standard deviation).
Semi-passive tags have three main advantages 1) Greater sensitivity than passive tags 2) Better battery life than active tags. 3) Can perform active functions (such as temperature logging) under its own power, even when no reader is present.
Antenna types
The antenna used for an RFID tag is affected by the intended application and the frequency of operation. Low-frequency (LF) passive tags are normally inductively coupled, and because the voltage induced is proportional to frequency, many coil turns are needed to produce enough voltage to operate an integrated circuit. Compact LF tags, like glass-encapsulated tags used in animal and human identification, use a multilayer coil (3 layers of 100–150 turns each) wrapped around a ferrite core.
At 13.56 MHz (High frequency or HF), a planar spiral with 5–7 turns over a credit-card-sized form factor can be used to provide ranges of tens of centimeters. These coils are less costly to produce than LF coils, since they can be made using lithographic techniques rather than by wire winding, but two metal layers and an insulator layer are needed to allow for the crossover connection from the outermost layer to the inside of the spiral where the integrated circuit and resonance capacitor are located.
Ultra-high frequency (UHF) and microwave passive tags are usually radiatively-coupled to the reader antenna and can employ conventional dipole-like antennas. Only one metal layer is required, reducing cost of manufacturing. Dipole antennas, however, are a poor match to the high and slightly capacitive input impedance of a typical integrated circuit. Folded dipoles, or short loops acting as inductive matching structures, are often employed to improve power delivery to the IC. Half-wave dipoles (16 cm at 900 MHz) are too big for many applications; for example, tags embedded in labels must be less than 100 mm (4 inches) in extent. To reduce the length of the antenna, antennas can be bent or meandered, and capacitive tip-loading or bowtie-like broadband structures are also used. Compact antennas usually have gain less than that of a dipole — that is, less than 2 dBi — and can be regarded as isotropic in the plane perpendicular to their axis.
Dipoles couple to radiation polarized along their axes, so the visibility of a tag with a simple dipole-like antenna is orientation-dependent. Tags with two orthogonal or nearly-orthogonal antennas, often known as dual-dipole tags, are much less dependent on orientation and polarization of the reader antenna, but are larger and more expensive than single-dipole tags.
Patch antennas are used to provide service in close proximity to metal surfaces, but a structure with good bandwidth is 3–6 mm thick, and the need to provide a ground layer and ground connection increases cost relative to simpler single-layer structures.
HF and UHF tag antennas are usually fabricated from copper or aluminum. Conductive inks have seen some use in tag antennas but have encountered problems with IC adhesion and environmental stability.
Tag attachment
There are three different kinds of RFID tags based on their attachment with identified objects, i.e. attachable, implantable and insertion tags . In addition to these conventional RFID tags, Eastman Kodak Company has filed two patent applications for monitoring ingestion of medicine comprises forming a digestible RFID tag[11].
Tagging positions
RFID tagging positions can influence the performance of air interface UHF RFID passive tags and related to the position where RFID tags are embedded, attached, injected or digested.
In many cases, optimum power from RFID reader is not required to operate passive tags. However, in cases where the Effective Radiated Power (ERP) level and distance between reader and tags are fixed, such as in manufacturing setting, it is important to know the location in a tagged object where a passive tag can operate optimally.
R-Spot or Resonance Spot, L-Spot or Live Spot and D-Spot or Dead Spot are defined to specify the location of RFID tags in a tagged object, where the tags can still receive power from a reader within specified ERP level and distance .
Tag environments
The proposed ubiquity of RFID tags means that readers may need to select which tags to read among many potential candidates, or may wish to probe surrounding devices to perform inventory checks or, in case the tags are associated to sensors and capable of keeping their values, question them for environmental conditions. If a reader intends to work with a collection of tags, it needs to either discover all devices within an area to iterate over them afterwards, or use collision avoidance protocols.
Finding tags in a search environment
In order to read tag data, readers use a tree-walking singulation algorithm, resolving possible collisions and processing responses one by one. Blocker tags may be used to prevent readers from accessing tags within an area without killing surrounding tags by means of suicide commands. These tags masquerade as valid tags but have some special properties: in particular, they may possess any identification code, and may deterministically respond to all reader queries, thus rendering them useless and securing the environment.
Besides this, tags may be promiscuous, attending all requests alike, or secure, which requires authentication and control of typical password management and secure key distribution issues. A tag may as well be prepared to be activated or deactivated in response to specific reader commands.
Readers that are in charge of the tags of an area may operate in autonomous mode (as opposed to interactive mode). When in this mode, a reader periodically locates all tags in its operating range, and keeps a presence list with a persist time and some control information. When an entry expires, it is removed from the list.
Frequently, a distributed application requires both types of tags: passive tags are incapable of continuous monitoring and perform tasks on demand when accessed by readers. They are useful when activities are regular and well defined, and requirements for data storage and security are limited; when accesses are frequent, continuous or unpredictable, there are time constraints to meet or data processing (internal searches, for instance) to perform, active tags may be preferred.
Current uses
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Passports
RFID tags are being used in passports issued by many countries. The first RFID passports ("E-passport") were issued by Malaysia in 1998. In addition to information also contained on the visual data page of the passport, Malaysian e-passports record the travel history (time, date, and place) of entries and exits from the country.
Standards for RFID passports are determined by the International Civil Aviation Organization (ICAO), and are contained in ICAO Document 9303, Part 1, Volumes 1 and 2 (6th edition, 2006). ICAO refers to the ISO 14443 RFID chips in e-passports as "contactless integrated circuits". ICAO standards provide for e-passports to be identifiable by a standard e-passport logo on the front cover.
In 2006, RFID tags were included in new
Transportation payments
- Throughout Europe, and in particular in Paris (system started in 1995 by the RATP), Lyon and Marseille in France, Porto and Lisbon in Portugal, Milan, Turin, and Florence in Italy, and Brussels in Belgium, RFID passes conforming to the Calypso (RFID) international standard are used for public transport systems. They are also used now in
RFID in a form of a sticker with bar code on the opposite side.
- T-money cards can be used to pay for public transit in
- JR East in Japan introduced SUICa (Super Urban Intelligent Card) for transport payment service in its railway transportation service in November 2001, using Sony's FeliCa (Felicity Card) technology. The same Sony technology was used in Hong Kong's Octopus card, and
- In Hong Kong, mass transit is paid for almost exclusively through the use of an RFID technology, called the Octopus Card. Originally it was launched in September 1997 exclusively for transit fare collection, but has grown to be similar to a cash card, and can stibe used in vending machines, fast-food restaurants and supermarkets. The card can be recharged with cash at add-value machines or in shops, and can be read several centimetres from the reader. The same applies for Delhi Metro, the rapid transit system in
An Electronic Road Pricing gantry in
- In
- RFID is used in Malaysia Expressways payment system. The name for the system is Touch 'n Go. Due to the name and design, one must touch the card for usage.
- The Washington, D.C. Metrorail became the first
- In Turkey, RFID has been used in the motorways and bridges as a payment system over ten years.
Product tracking
- The Canadian Cattle Identification Agency began using RFID tags as a replacement for barcode tags. The tags are required to identify a bovine's herd of origin and this is used for tracing when a packing plant condemns a carcass. Currently CCIA tags are used in
RFID tags used in libraries: square book tag, round CD/DVD tag and rectangular VHS tag.
RFID in inventory systems
An advanced automatic identification technology such as the Auto-ID system based on the Radio Frequency Identification (RFID) technology has two values for inventory systems. First, the visibility provided by this technology allows an accurate knowledge on the inventory level by eliminating the discrepancy between inventory record and physical inventory. In an academic study performed at Wal-Mart, RFID reduced Out of Stocks by 30 percent for products selling between 0.1 and 15 units a day. Second, the RFID technology can prevent or reduce the sources of errors. *Benefits of using RFID include the reduction of labour costs, the simplification of business processes and the reduction of inventory inaccuracies.
Human implants
Hand with the planned location of the RFID chip
Just after the operation to insert the RFID tag was completed
Implantable RFID chips designed for animal tagging are now being used in humans. An early experiment with RFID implants was conducted by British professor of cybernetics Kevin Warwick, who implanted a chip in his arm in 1998. Night clubs in Barcelona, Spain and in Rotterdam, The Netherlands, use an implantable chip to identify their VIP customers, who in turn use it to pay for drinks.
In 2004, the Mexican Attorney General's office implanted 18 of its staff members with the Verichip to control access to a secure data room. (This number has been variously mis-reported as 160 or 180 staff members.)
Security experts are warned against using RFID for authenticating people due to the risk of identity theft. For instance a man-in-the-middle attack would make it possible for an attacker to steal the identity of a person in real-time. Due to the resource-constraints of RFIDs it is virtually impossible to protect against such attack models as this would require complex distance-binding protocols.
RFID in libraries
Among the many uses of RFID technologies is its deployment in libraries. This technology has slowly begun to replace the traditional barcodes on library items (books, CDs, DVDs, etc.). However, the RFID tag can contain identifying information, such as a book’s title or material type, without having to be pointed to a separate database (but this is rare in
A concern surrounding RFID in libraries that has received considerable publicity is the issue of privacy. Because RFID tags can in theory be scanned and read from over 350 feet in distance, and because RFID utilizes an assortment of frequencies, there is a legitimate concern over whether sensitive information could be collected from an unwilling source. However, advocates of RFID’s use in libraries will point out that library RFID tags do not contain any patron information, and that the tags used in the majority of libraries use a frequency only readable from approximately ten feet. There is much yet to be written and discussed on the issue of privacy and RFID, but it is clear that vendors need to be aware of this issue and develop improved technologies for secure RFID transactions.
Schools and Universities
School authorities in the Japanese city of Osaka are now chipping children's clothing, back packs, and student ids in a primary school. A school in Doncaster, England is piloting a monitoring system designed to keep tabs on pupils by tracking radio chips in their uniforms.
Other
· Some hospitals use Active RFID tags to perform Asset Tracking in Real Time.
· In 2006, the Smart Conveyer Tunnel, designed by Blue Vector, was introduced. This allowed the pharmaceutical industry to track both UHF and HF tags. Rite Aid utilized the technology with some of McKesson's products.
· The NEXUS and SENTRI frequent traveler programs use RFID to speed up landborder processing between the U.S. and Canada and Mexico.
· NADRA has developed an RFID-based driver license that bears the license holders personal information and stores data regarding traffic violations, tickets issued, and outstanding penalties. The license cards are designed so that driving rights can be revoked electronically in case of serious violations.
· Sensors such as seismic sensors may be read using RFID transceivers, greatly simplifying remote data collection.
· In August 2004, the Ohio Department of Rehabilitation and Correction (ODRC) approved a $415,000 contract to evaluate the personnel tracking technology of Alanco Technologies. Inmates will wear wristwatch-sized transmitters that can detect attempted removal and alert prison computers. This project is not the first rollout of tracking chips in US prisons. Facilities in Michigan,
· Automatic timing at mass sports events "ChampionChip".
· Used as storage for a video game system produced by Mattel, "HyperScan".
Potential uses
Replacing barcodes
RFID tags are often envisioned as a replacement for UPC or EAN barcodes, having a number of important advantages over the older barcode technology. They may not ever completely replace barcodes, due in part to their higher cost and in other part to the advantage of more than one independent data source on the same object. The new EPC, along with several other schemes, is widely available at reasonable cost.
The storage of data associated with tracking items will require many terabytes on all levels. Filtering and categorizing RFID data is needed in order to create useful information. It is likely that goods will be tracked preferably by the pallet using RFID tags, and at package level with Universal Product Code (UPC) or EAN from unique barcodes.
The unique identity in any case is a mandatory requirement for RFID tags, despite special choice of the numbering scheme. RFID tag data capacity is big enough that any tag will have a unique code, while current bar codes are limited to a single type code for all instances of a particular product. The uniqueness of RFID tags means that a product may be individually tracked as it moves from location to location, finally ending up in the consumer's hands. This may help companies to combat theft and other forms of product loss. Moreover, the tracing back of products is an important feature that gets well supported with RFID tags containing not just a unique identity of the tag but also the serial number of the object. This may help companies to cope with quality deficiencies and resulting recall campaigns, but also contributes to concern over post-sale tracking and profiling of consumers.
It has also been proposed to use RFID for POS store checkout to replace the cashier with an automatic system which needs no barcode scanning. However, this is not likely to be possible without a significant reduction in the cost of current tags and changes in the operational process around POS. There is some research taking place, however, this is some years from reaching fruition.
Telemetry
Active RFID tags also have the potential to function as low-cost remote sensors that broadcast telemetry back to a base station. Applications of tagometry data could include sensing of road conditions by implanted beacons, weather reports, and noise level monitoring.
Patient identification
In July 2004, the Food and Drug Administration issued a ruling that essentially begins a final review process that will determine whether hospitals can use RFID systems to identify patients and/or permit relevant hospital staff to access medical records. Since then, a number of U.S. hospitals have begun implanting patients with RFID tags and using RFID systems, more generally, for workflow and inventory management. The use of RFID to prevent mixups between sperm and ova in IVF clinics is also being considered .
In October 2004, the FDA approved
Regulation and standardization
There is no global public body that governs the frequencies used for RFID. In principle, every country can set its own rules for this. The main bodies governing frequency allocation for RFID are:
CONCLUSION:
Technology always brings importance to the society along with its disadvantages. So earlier methods of identification of an authorized user like fingerprints: which have a disadvantage like if an authorized person accidentally has an injury to his finger he himself cannot access his own product. Next comes face recognition, in face recognition again we have a problem like any one have a plastic surgery and can access our product .There comes the reason of inventing a product which can be stored inside our body so that no one can change us or cheat us, this paved the way for an innovative idea of RFID, from the above uses we can assume that it brings a lot of advantages in this insecure world.
