Standing for radio Frequency Identification, RFID is a contactless identification technology that has been developed for storing and retrieving data at a distance using a transmitter/receiver system (reader) and markers (tags).
RFID tags are small objects such as adhesive labels, badges, key fobs etc. containing an integrated circuit and an antenna for receiving and responding to radio signals transmitted by the transmitter/receiver (reader). The circuits contain an identifier and may also host other data.
Readers are active items of equipment emitting radiofrequency signals that activate any tags entering their field by providing the energy required by the tag.
How does it work?
When the tags (also known as transponders) are "woken" by the reader, a predefined communication protocol is used for data exchange between the items. Unlike barcodes, RFID do not require the reader to be brought close to the product to enable the identification process. Tags can be read in a range of a few centimetres to several tens of metres in some cases, and can be beyond the line of sight of the reader. Depending on the model used, tags may have read-only functionality or allow additional information to be written to them.
In order to communicate, the tag and reader need to be on the same frequency, but like a radio set, the frequencies can be on a wide spectrum from low to very high frequencies. RFID tags are formed by the pairing of an integrated circuit (chip) and an antenna and are affixed on a product or container.
The antenna is tuned to a specific frequency, and captures the electromagnetic signal sent by the reader. Some tags are referred to as "passive". In this case, the signal has to have a certain power and uses induction to generate a current in the chip. "Active" or "semi-active" tags come with a battery to power the chip. The signal required with such chips can be lower-power and can be received over a greater distance. This signal simply activates the tag.
Once the activation signal is received, the chip transmits the information it contains. Some tags also have a memory system enabling data to be written to them.
Unlike with barcode systems, if multiple tags are in the reader's field, information will be transmitted by all the tags at the same time and the reader has to process the stream of data together.
RFID technology can be used to identify:
- products (as with a barcode);
- people, transport passes, payment cards, access badges (referred to as contactless cards) for access control and time-clocking applications, etc.
Standards and frequencies
Several communications frequencies can be used by RFID technology:
- Low frequency: 125 kHz
- High frequency: 13.56 MHz
- Ultra-high frequency: 433 MHz, 863 to 915 MHz, 2.45 GHz
Each country reserves the right to allocate these frequencies to other specific uses, taking into account the transmission power. Frequency usage is currently being standardised and defined in three world regions:
- Region 1 = Europe and Africa
- Region 2 = North and South America
- Region 3 = Asia and Australia
Current trends suggest that the market for RFID solutions will grow rapidly over the next 10 years. The overall market value (including hardware, systems and services) is set to increase tenfold between 2006 and 2016. The number of tags is anticipated to increase 450 times over the same period.
Significant growth in RFID application is expected, particularly in the fields of transport, logistics, access control, supply chain management, inventory management and healthcare.