RFID - RF-ID - RF Identification
RF Identification, or RF-ID or RFID, is the use of electronic tags to identify persons and animals and to identify, track, sort or detect a wide variety of objects (e.g. pallets, cases, containers around factories or in warehouses).
An RFID system consists of three basic components, namely the tag, the reader and the middleware. The tag uniquely identifies the item to which it is affixed and communicates with the reader via radio signals. The reader then converts the radio signals into data that can be passed onto the middleware (which determines what the specific RFID system does) to trigger further actions, based on the identifying information.
The RFID tag consists of a powered or nonpowered microchip and an antenna. Passive tags are the simplest, smallest and cheapest version of an RFID tag as they do not contain a built-in power source and consequently cannot initiate communication with a reader. As the available power from the reader field diminishes rapidly with distance, passive tags have practical read ranges that vary from about 10 mm up to about 5 metres.
Semi-passive tags have built-in batteries to power the chip on the tag. They use power from the RFID reader to respond. Due to the use of batteries, semi-passive tags are faster and stronger to respond back on receiving a signal compared to passive tags. This allows them to act over greater distances. Active tags are battery powered devices that have an active transmitter onboard. They can communicate over longer distances (several kilometres) and have read/write capabilities allowing tag data to be rewritten or modified over the lifecycle.
The reader is a handheld or fixed device that uses radiowaves to activate and obtain data from RFIDs in the vicinity. It can be seen as the tags’ gateway to the data processing system. It scans multiple tags without requiring line-of-sight and communicates the results to the middleware. The power output and the radio frequency determine the range at which the tags can be read. Readers can be distinguished by their storage and processing capacity, and by the frequencies at which they operate.
RFID middleware consists of computer hardware and data processing software that connects readers to computer systems and data repositories. It converts data from tags into tracking or identification information. It may also help filter data more effectively, and remotely monitor, control and maintain readers.
The current frequency allocations for RFID are mainly in the 120-148.5 kHz, 13.56 MHz, 865-868 MHz and 2.4 GHz frequency bands.