Radio-frequency identification (RFID) is the wireless non-contact use of radio-frequency electromagnetic fields to transfer data, for the purposes of automatically identifying and tracking tags attached to objects. The tags contain electronically stored information. Some tags are powered and read at short ranges (a few meters) via magnetic fields (electromagnetic induction). Others use a local power source such as a battery, or else have no battery but collect energy from the interrogating EM field, and then act as a passive transponder to emit microwaves or UHF radio waves (i.e., electromagnetic radiation at high frequencies). Battery powered tags may operate at hundreds of meters. Unlike a bar code, the tag does not necessarily need to be within line of sight of the reader, and may be embedded in the tracked object.
Radio-frequency identification (RFID) is an automatic identification method wherein the data stored on RFID tags or transponders is remotely retrieved. The RFID tag is a device that can be attached to or incorporated into a product, animal or person for identification and tracking using radio waves. Some tags can be read from several metres away, beyond the line of sight of the reader.
Basically, an RFID system consists of an antenna or coil, a transceiver (with decoder) and a transponder (RF tag) electronically programmed with unique information. There are many different types of RFID systems in the market. These are categorised on the basis of their frequency ranges. Some of the most commonly used RFID kits are low-frequency (30-500kHz), mid-frequency (900kHz-1500MHz) and high-frequency (2.4-2.5GHz).
This image shows the internal diagram of a typical RFID antenna. The antenna emits radio signals to activate the tag and read/write data from/to it. It is the conduit between the tag and the transceiver, which controls the system’s data acquisition and communication.
Antennae are available in a variety of shapes and sizes. These can be built into a door frame to receive tag data from persons or things passing through the door, or mounted on an inter-state tollbooth to monitor the traffic passing by on a freeway. The electromagnetic field produced by the antenna can be constantly present when multiple tags are expected continually. If constant interrogation is not required, a sensor device can activate the field.
Often the antenna is packaged with a transceiver and decoder to act as a reader (interrogator), which can be configured either as a handheld or a fixed-mount device. The reader emits radio waves in the range of 2.5 cm to 30 metres or more, depending upon its power output and the radio frequency used. When an RFID tag passes through the electromagnetic zone, it detects the reader’s activation signal. The reader decodes the data encoded in the tag’s integrated circuit (silicon chip) and communicates to the host computer for processing.
Commerce
Asset management : RFID combined with mobile computing and Web technologies provide a way for organizations to identify and manage their assets. Mobile computers, with integrated RFID readers, can now deliver a complete set of tools that eliminate paperwork, give proof of identification and attendance. This approach eliminates manual data entry.
Inventory systems : An advanced automatic identification technology based on RFID technology has significant value for inventory systems. The system can provide accurate knowledge of the current inventory. The RFID can also help the company to ensure the security of the inventory.
Product tracking : RFID use in product tracking applications begins with plant-based production processes, and then extends into post-sales configuration management policies for large buyers.
Access control : RFID tags are widely used in identification badges, replacing earlier magnetic stripe cards. These badges need only be held within a certain distance of the reader to authenticate the holder.
Social media : Facebook is using RFID cards at most of their live events to allow guests to automatically capture and post photos. The automotive brands have adopted RFID for social media product placement more quickly than other industries.
Promotion tracking : To prevent retailers diverting products, manufacturers are exploring the use of RFID tags on promoted merchandise so that they can track exactly which product has sold through the supply chain at fully discounted prices.
Transportation and logistics : Logistics and transportation are major areas of implementation for RFID technology. Yard management, shipping and freight and distribution centers use RFID tracking technology. In the rail-road industry, RFID tags mounted on locomotives and rolling stock identify the owner, identification number and type of equipment and its characteristics.
Infrastructure management and protection : At least one company has introduced RFID technology to identify and locate underground infrastructure assets such as gas pipelines, sewer lines, electrical cables, communication cables, etc.
Passports : The first RFID passports ("E-passport") were issued by Malaysia in 1998. Since 2006, RFID tags included in new US passports will store the same information that is printed within the passport and also include a digital picture of the owner.
Transportation payments : In many countries, RFID tags can be used to pay for mass transit fares on bus, trains, or subways, or to collect tolls on highways.Animal identification : RFID tags for animals represent one of the oldest uses of RFID technology. Originally meant for large ranches and rough terrain, since the outbreak of mad-cow disease, RFID has become crucial in animal identification management.
Human identification : 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. In 2004 Conrad Chase offered implanted chips in his night clubs in Barcelona and Rotterdam to identify their VIP customers, who in turn use it to pay for drinks.
Institutions
Hospitals and healthcare : Adoption of RFID in the medical industry has been widespread and very effective. Hospitals are among the first users to combine both active and passive RFID technology. Many successful deployments in the healthcare industry have been cited where active technology tracks high-value, or frequently moved items, where passive technology tracks smaller, lower cost items that only need room-level identification.
Libraries : Libraries have used RFID to replace the barcodes on library items. The tag can contain identifying information or may just be a key into a database. An RFID system may replace or supplement bar codes and may offer another method of inventory management and self-service checkout by patrons. It can also act as a security device, taking the place of the more traditional electromagnetic security strip.
Museums : RFID technologies are now also implemented in end-user applications in museums.
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.
Sports : RFID for timing races began in the early 1990s with pigeon racing, introduced by the company Deister Electronics in Germany. RFID can provide race start and end timings for individuals in large races where it is impossible to get accurate stopwatch readings for every entrant.
Complement to barcode : RFID tags are often a complement, but not a substitute, for UPC or EAN barcodes. They may never completely replace barcodes, due in part to their higher cost and the advantage of multiple data sources on the same object. Also, unlike RFID labels, barcodes can be generated and distributed electronically.
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.
Data flooding : Not every successful reading of a tag (observation) represents data useful for the purposes of the business. A large amount of data may be generated that is not useful for managing inventory or other applications. For example, a customer moving a product from one shelf to another, or a pallet load of articles that passes several readers while being moved in a warehouse, are events that do not produce data that is meaningful to an inventory control system.
Security concerns : Retailers such as Walmart, which already heavily use RFID technology for inventory purposes, also use RFID as an anti-employee-theft and anti-shoplifting technology. If a product with an active RFID tag passes the exit-scanners at a Walmart outlet, not only does it set off an alarm, but it also tells security personnel exactly what product to look for in the shopper's cart.
Exploitation : Ars Technica reported in March 2006 an RFID buffer overflow bug that could infect airport terminal RFID databases for baggage, and also passport databases to obtain confidential information on the passport holder.
Passports : In an effort to make passports more secure, several countries have implemented RFID in passports. However, the encryption on UK chips was broken in under 48 hours. Since that incident, further efforts have allowed researchers to clone passport data while the passport is being mailed to its owner. Where a criminal used to need to secretly open and then reseal the envelope, now it can be done without detection, adding some degree of insecurity to the passport system.
Shielding : In an effort to prevent the passive “skimming” of RFID-enabled cards or passports, the U.S. General Services Administration (GSA) issued a set of test procedures for evaluating electromagnetically opaque sleeves. For shielding products to be in compliance with FIPS-201 guidelines, they must meet or exceed this published standard. Shielding products currently evaluated as FIPS-201 compliant are listed on the website of the U.S. CIO’s FIPS-201 Evaluation Program. The United States government requires that when new ID cards are issued, they must be delivered with an approved shielding sleeve or holder.
Temperature exposure : Currently, RFID tags are created by gluing an integrated circuit (IC) to an inlay. This poses a problem as vibration and high temperatures will loosen the connection. If the IC loses connection with the inlay, the RFID tag will no longer transmit. A new design was filed for patent (currently pending approval) where the IC is soldered to a circuit board and the circuit board is then soldered to the inlay. This process replaces the adhesive with solder which is much more durable and temperature resistant.
Privacy : Since the owner of an item will not necessarily be aware of the presence of an RFID tag and the tag can be read at a distance without the knowledge of the individual, it becomes possible to gather sensitive data about an individual without consent. If a tagged item is paid for by credit card or in conjunction with use of a loyalty card, then it would be possible to indirectly deduce the identity of the purchaser by reading the globally unique ID of that item (contained in the RFID tag). This is only true if the person doing the watching also had access to the loyalty card data and the credit card data, and the person with the equipment knows where you are going to be.
Government control : With the rise of technology, some individuals have grown to fear the loss of rights due to RFID human implantation. By early 2007, Chris Paget of San Francisco, California, showed that RFID information can be pulled from individuals by using only $250 worth of equipment. This supports the claim that with the information captured, it would be relatively simple to make counterfeit passports
Deliberate destruction in clothing and other items : According to an RSA laboratories FAQ, RFID tags can be destroyed by a standard microwave oven; however some types of RFID tags, particularly those constructed to radiate using large metallic antennas (in particular RF tags and EPC tags), may catch fire if subjected to this process for too long (as would any metallic item inside a microwave oven). This simple method cannot safely be used to deactivate RFID features in electronic devices, or those implanted in living tissue, because of the risk of damage to the "host". However the time required is extremely short (a second or two of radiation) and the method works in many other non-electronic and inanimate items, long before heat or fire become of concern.
RFID tags are used in many industries. An RFID tag attached to an automobile during production can be used to track its progress through the assembly line. Pharmaceuticals can be tracked through warehouses. Livestock and pets may have tags injected, allowing positive identification of the animal.
Since RFID tags can be attached to clothing, possessions, or even implanted within people, the possibility of reading personally-linked information without consent has raised privacy concerns.
Since RFID tags can be attached to clothing, possessions, or even implanted within people, the possibility of reading personally-linked information without consent has raised privacy concerns.
RFID system fundamentals
Antennae are available in a variety of shapes and sizes. These can be built into a door frame to receive tag data from persons or things passing through the door, or mounted on an inter-state tollbooth to monitor the traffic passing by on a freeway. The electromagnetic field produced by the antenna can be constantly present when multiple tags are expected continually. If constant interrogation is not required, a sensor device can activate the field.
Often the antenna is packaged with a transceiver and decoder to act as a reader (interrogator), which can be configured either as a handheld or a fixed-mount device. The reader emits radio waves in the range of 2.5 cm to 30 metres or more, depending upon its power output and the radio frequency used. When an RFID tag passes through the electromagnetic zone, it detects the reader’s activation signal. The reader decodes the data encoded in the tag’s integrated circuit (silicon chip) and communicates to the host computer for processing.
Tags (transponders)
This image shows the internal structure of a typical RFID tag. It comprises a microchip containing identifying information about the item and an antenna that transmits this data wirelessly to the reader. At its most basic, the chip contains a serialised identifier or licence plate number that uniquely identifies that item (similar to bar codes). A key difference, however, is that RFID tags have a higher data capacity than their bar code counterparts. This increases the options for the type of information that can be encoded on the tag; it may include the manufacturer’s name, batch or lot number, weight, ownership, destination and history (such as the temperature range to which an item has been exposed). In fact, an unlimited list of other types of information can be stored on RFID tags, depending on the application’s requirements.
RFID tag can be placed on individual items, cases or pallets for identification purposes, as well as fixed assets such as trailers, containers and totes. There are different types of tags with varying capabilities:
1. Read-only tags contain such data as a serialised tracking number, which is pre-written onto these by the tag manufacturer or distributor. These are generally the least expensive tags as no additional information can be included when they move through the supply chain. Any update to the information has to be maintained in the application software that tracks the stock-keeping unit’s movement and activity.2. Write-once tags enable the user to write data once in the production or distribution process. The data may include a serial number or lot or batch number.
3. Full read-write tags allow new data to be written to the tag—even over the original data—when needed. Examples include the time and date of ownership transfer or updating the repair history of a fixed asset. While these are the most costly of the three tag types and impractical for tracking inexpensive items, future standards for electronic product codes (EPCs) appear to be headed in this direction.
Other features of the tag include:
RFID tag can be placed on individual items, cases or pallets for identification purposes, as well as fixed assets such as trailers, containers and totes. There are different types of tags with varying capabilities:
1. Read-only tags contain such data as a serialised tracking number, which is pre-written onto these by the tag manufacturer or distributor. These are generally the least expensive tags as no additional information can be included when they move through the supply chain. Any update to the information has to be maintained in the application software that tracks the stock-keeping unit’s movement and activity.2. Write-once tags enable the user to write data once in the production or distribution process. The data may include a serial number or lot or batch number.
3. Full read-write tags allow new data to be written to the tag—even over the original data—when needed. Examples include the time and date of ownership transfer or updating the repair history of a fixed asset. While these are the most costly of the three tag types and impractical for tracking inexpensive items, future standards for electronic product codes (EPCs) appear to be headed in this direction.
Other features of the tag include:
Data capacity : The capacity of data storage on a tag can vary from 16 bits to several thousand bits. Of course, the greater the storage capacity, the higher the price of the tag.
Form factor : The tag and antenna structure can come in a variety of physical form factors and can either be self-contained or embedded as part of a traditional label structure (termed as ‘smart label,’ it has the tag inside what looks like a regular bar code label).
Passive and active : Passive tags have no battery and broadcast their data only when energised by a reader. It means these must be actively polled to send information. Active tags broadcast data using their battery power. This means their read range is greater than passive tags—around 30 metres or more, versus 5 metres or less for most passive tags.
The extra capability and read range of active tags, however, come at a cost. These are several times more expensive than passive tags. Today, active tags are much more likely to be used for high-value items or fixed assets such as trailers, where the cost is minimal compared to item value and very long read ranges are required. Most traditional supply chain applications, such as the RFID-based tracking and compliance programmes emerging in the consumer goods retail chain, use the less expensive passive tags.
Frequency range : Like all wireless communications, there are a variety of frequencies or spectra through which RFID tags communicate with readers. Again, there are trade-offs among cost, performance and application requirements. For instance, low-frequency tags are cheaper than ultra-high-frequency (UHF) tags, use less power and are better able to penetrate non-metallic substances. These are ideal for scanning objects with high water content, such as fruit, at close ranges.
UHFs typically offer longer range and can transfer data faster. But these use more power and are less likely to be effective with some materials.
Electronic product code (EPC) tags : EPC is an emerging specification for RFID tags, readers and business applications. It represents a specific approach to item identification, including an emerging standard for the tags—with both the data content of the tag and open wireless communication protocols.
RF transceiver : RF transceiver is the source of RF energy used to activate and power the passive RFID tags. It may be enclosed in the same cabinet as the reader or it may be a separate piece of equipment. When provided as a separate piece of equipment, the transceiver is commonly referred to as an RF module. RF transceiver controls and modulates the radio frequencies that the antenna transmits and receives. The transceiver filters and amplifies the backscatter signal from a passive RFID tag.
Form factor : The tag and antenna structure can come in a variety of physical form factors and can either be self-contained or embedded as part of a traditional label structure (termed as ‘smart label,’ it has the tag inside what looks like a regular bar code label).
Passive and active : Passive tags have no battery and broadcast their data only when energised by a reader. It means these must be actively polled to send information. Active tags broadcast data using their battery power. This means their read range is greater than passive tags—around 30 metres or more, versus 5 metres or less for most passive tags.
The extra capability and read range of active tags, however, come at a cost. These are several times more expensive than passive tags. Today, active tags are much more likely to be used for high-value items or fixed assets such as trailers, where the cost is minimal compared to item value and very long read ranges are required. Most traditional supply chain applications, such as the RFID-based tracking and compliance programmes emerging in the consumer goods retail chain, use the less expensive passive tags.
Frequency range : Like all wireless communications, there are a variety of frequencies or spectra through which RFID tags communicate with readers. Again, there are trade-offs among cost, performance and application requirements. For instance, low-frequency tags are cheaper than ultra-high-frequency (UHF) tags, use less power and are better able to penetrate non-metallic substances. These are ideal for scanning objects with high water content, such as fruit, at close ranges.
UHFs typically offer longer range and can transfer data faster. But these use more power and are less likely to be effective with some materials.
Electronic product code (EPC) tags : EPC is an emerging specification for RFID tags, readers and business applications. It represents a specific approach to item identification, including an emerging standard for the tags—with both the data content of the tag and open wireless communication protocols.
RF transceiver : RF transceiver is the source of RF energy used to activate and power the passive RFID tags. It may be enclosed in the same cabinet as the reader or it may be a separate piece of equipment. When provided as a separate piece of equipment, the transceiver is commonly referred to as an RF module. RF transceiver controls and modulates the radio frequencies that the antenna transmits and receives. The transceiver filters and amplifies the backscatter signal from a passive RFID tag.
USES
Payment by mobile phones :When inserted into a mobile phone, the microSD card can be both a passive tag and an RFID reader.After inserting the microSD, a user's phone can be linked to bank accounts and used in mobile payment.
Hospitals and healthcare : Adoption of RFID in the medical industry has been widespread and very effective. Hospitals are among the first users to combine both active and passive RFID technology. Many successful deployments in the healthcare industry have been cited where active technology tracks high-value, or frequently moved items, where passive technology tracks smaller, lower cost items that only need room-level identification.
Libraries : Libraries have used RFID to replace the barcodes on library items. The tag can contain identifying information or may just be a key into a database. An RFID system may replace or supplement bar codes and may offer another method of inventory management and self-service checkout by patrons. It can also act as a security device, taking the place of the more traditional electromagnetic security strip.
Museums : RFID technologies are now also implemented in end-user applications in museums.
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.
Sports : RFID for timing races began in the early 1990s with pigeon racing, introduced by the company Deister Electronics in Germany. RFID can provide race start and end timings for individuals in large races where it is impossible to get accurate stopwatch readings for every entrant.
Complement to barcode : RFID tags are often a complement, but not a substitute, for UPC or EAN barcodes. They may never completely replace barcodes, due in part to their higher cost and the advantage of multiple data sources on the same object. Also, unlike RFID labels, barcodes can be generated and distributed electronically.
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.
Problems
Data flooding : Not every successful reading of a tag (observation) represents data useful for the purposes of the business. A large amount of data may be generated that is not useful for managing inventory or other applications. For example, a customer moving a product from one shelf to another, or a pallet load of articles that passes several readers while being moved in a warehouse, are events that do not produce data that is meaningful to an inventory control system.
Global standardization : The frequencies used for UHF RFID in the USA are currently incompatible with those of Europe or Japan. Furthermore, no emerging standard has yet become as universal as the barcode. To address international trade concerns, it is necessary to use a tag that is operational within all of the international frequency domains.
Security concerns : Retailers such as Walmart, which already heavily use RFID technology for inventory purposes, also use RFID as an anti-employee-theft and anti-shoplifting technology. If a product with an active RFID tag passes the exit-scanners at a Walmart outlet, not only does it set off an alarm, but it also tells security personnel exactly what product to look for in the shopper's cart.
Exploitation : Ars Technica reported in March 2006 an RFID buffer overflow bug that could infect airport terminal RFID databases for baggage, and also passport databases to obtain confidential information on the passport holder.
Passports : In an effort to make passports more secure, several countries have implemented RFID in passports. However, the encryption on UK chips was broken in under 48 hours. Since that incident, further efforts have allowed researchers to clone passport data while the passport is being mailed to its owner. Where a criminal used to need to secretly open and then reseal the envelope, now it can be done without detection, adding some degree of insecurity to the passport system.
Shielding : In an effort to prevent the passive “skimming” of RFID-enabled cards or passports, the U.S. General Services Administration (GSA) issued a set of test procedures for evaluating electromagnetically opaque sleeves. For shielding products to be in compliance with FIPS-201 guidelines, they must meet or exceed this published standard. Shielding products currently evaluated as FIPS-201 compliant are listed on the website of the U.S. CIO’s FIPS-201 Evaluation Program. The United States government requires that when new ID cards are issued, they must be delivered with an approved shielding sleeve or holder.
Temperature exposure : Currently, RFID tags are created by gluing an integrated circuit (IC) to an inlay. This poses a problem as vibration and high temperatures will loosen the connection. If the IC loses connection with the inlay, the RFID tag will no longer transmit. A new design was filed for patent (currently pending approval) where the IC is soldered to a circuit board and the circuit board is then soldered to the inlay. This process replaces the adhesive with solder which is much more durable and temperature resistant.
Controversies
Privacy : Since the owner of an item will not necessarily be aware of the presence of an RFID tag and the tag can be read at a distance without the knowledge of the individual, it becomes possible to gather sensitive data about an individual without consent. If a tagged item is paid for by credit card or in conjunction with use of a loyalty card, then it would be possible to indirectly deduce the identity of the purchaser by reading the globally unique ID of that item (contained in the RFID tag). This is only true if the person doing the watching also had access to the loyalty card data and the credit card data, and the person with the equipment knows where you are going to be.
Government control : With the rise of technology, some individuals have grown to fear the loss of rights due to RFID human implantation. By early 2007, Chris Paget of San Francisco, California, showed that RFID information can be pulled from individuals by using only $250 worth of equipment. This supports the claim that with the information captured, it would be relatively simple to make counterfeit passports
Deliberate destruction in clothing and other items : According to an RSA laboratories FAQ, RFID tags can be destroyed by a standard microwave oven; however some types of RFID tags, particularly those constructed to radiate using large metallic antennas (in particular RF tags and EPC tags), may catch fire if subjected to this process for too long (as would any metallic item inside a microwave oven). This simple method cannot safely be used to deactivate RFID features in electronic devices, or those implanted in living tissue, because of the risk of damage to the "host". However the time required is extremely short (a second or two of radiation) and the method works in many other non-electronic and inanimate items, long before heat or fire become of concern.