Introduction to RFID
RFID (Radio frequency identification) is a generic term for technologies that use radio waves to automatically identify objects (including human beings and animals). There are several methods of identification, but the most common is to store a serial number that identifies a person or object, and perhaps other information, on a microchip that is attached to an antenna (the chip and the antenna together are called an RFID transponder or an RFID tag). The antenna enables the chip to transmit the identification information to a reader. The reader converts the radio waves reflected back from the RFID tag into digital information that can then be passed on to computers that can make use of it.
RFID is a rapidly growing technology that has the potential to make great economic impacts on many industries. While RFID is a relatively old technology, more recent advancements in chip manufacturing technology are making RFID practical for new applications and settings, particularly consumer item level tagging. These advancements have the potential to revolutionize supply-chain management, inventory control, and logistics.
How does RFID System work
At its most basic, RFID systems consist of small transponders, or tags, which is made up of a microchip with an antenna and attached to physical objects. RFID tags may soon become the most pervasive microchip in history. When wirelessly interrogated by RFID transceivers, or readers, tags respond with some identifying information that may be associated with arbitrary data records. Thus, RFID systems are one type of automatic identification system, similar to optical bar codes; however one big difference between RFID and bar code technology is that RFID does not rely on the line-of-sight reading that bar code scanning requires to work with.
1. Reader (Interrogator)
2. Tag (Transponder)
- Master/Slave operation.
- The Reader detects any Tag within its zone of operation.
- Uplink: Reader sends commands, clock, and power needed to operate the tag.
- Tag is activated by the RF signal.
- Downlink: Tag sends response (simple Id, or sensor data).
- RFID tags consist of a microchip and a coupling element - an antenna.
- These tags can be both read-only (programmed during manufacture) or, at higher complexity and cost, read-write, or both.
- The tags contain memory.
- The size of the tag depends on the size of the antenna, which increases with range of tag and decreases with frequency.
Type of Tags
- Passive tag is the form deficient in energy and dependent on the cross-examiner called interrogator to find out its identity.
- Crossbreed tag is a combination of passive and active, having a built-in, low-energy battery.
- Active tags are built-in with battery enabling it instantaneous communication with interrogators.
Differences between Passive and Active Tags
|Passive Tags||Active Tags|
|Do not require a power source to operate||Powered by an internal battery with a finite lifespan|
|Short range||Long range|
|Sensitive to interference||Less sensitive to interference|
|Low data transmission rates||High data transmission rates|
|Can read few tags at once||Can read many tags at once|
|Readers needs to be aimed at the tag||Tags can be read without precise aiming|
- The RFID Reader, which is also widely known as interrogator, sends RF signal to request tag for transmitting information within the chip.
- The response received from the tag is then translated in to digital form and send to the application software.
- Different types of readers are fixed readers, handheld readers, network readers, readers embedded in other mobile devices etc...
- Some interrogators not only read, but also remotely write to, the tags.
Type of readers
- RFID readers offer an easy-to-carry wireless form factor that allows workers to take the reader to the RFID tag — unlike fixed readers, which require workflows that bring the items to the reader.
- Fixed readers are designed for large-scale deployments that need to process a large volume of assets at choke points and primary read zones, such as dock doors.
- Mobile RFID reader is cable-free device is completely self-contained, with integrated battery, antennas and wireless communications capabilities. The mobile RFID reader can be used on material handling equipment, such as forklifts, clamp trucks and skate wheels or on other moving equipment like mobile carts.
- The antenna transmits an electromagnetic field, which activates the tag.
- It also receives the data from the tag and sends it to the reader
- Tags also require an antenna to transmit the information to the reader and to receive information from the reader if it is a rewritable tag.
- Middleware is the interface needed between the interrogator and the existing company databases and information management software.
Differences between Passive and Active Tags
|Task||RFID||Other identifying technologies such as Barcode|
||Up to 5 feet|
|Read Rate||10’s, 100’s or 1000’s simultaneously||Only one at a time|
|Identification||Can uniquely identify each item/asset tagged||Can typically only identify the type of the item (UPC code) but not uniquely|
|Read/Write||Many RFID tags are read/write enabled||Read only|
|Technology||RF (Radio Frequency)||Optical (Laser)|
|Interference||Like the TSA (Transportation Security Administration), some RFID frequencies don’t like metal and Liquids. They can cause interfere with certain RF frequencies.||Obstructed barcodes cannot be read (dirt covering barcode, torn barcode, et…)|
|Automation||Most “fixed” readers don’t require human involvement to collect data (automated)||Most barcode scanners require human involvement to operate (labour intensive).|
RFID systems are becoming a part of our everyday life: at home, work, in hospitals, post offices, supermarkets, tracking our pets, implanted in human bodies and many more possibilities.
The application areas could be categorized:
a) Tracking and identification:
- Large assets, e.g. railway cars, Airbuses and shipping containers
- Livestock with rugged tags
- Pets with implanted tags
- Supply-chain management with EPC (Electronic Product Code)
- Inventory control with EPC
- Retail checkout with EPC
- Recycling and waste disposal
- Library management
b) Payment and stored-value systems:
- Electronic toll systems
- Contact-less Credit Cards, e.g. American Express Blue card
- Stored-valued systems, e.g. ExxonMobil Speed pass
- Subway and bus passes
- Casino tokens
c) Access control:
- Building access with proximity cards
- Ski-lift passes
- Concert tickets
- Automobile ignition systems
- Casino tokens
- High-denomination currency notes
- Luxury goods such as Prada
- Prescription drugs