RFID stands for Radio Frequency Identification, and describes one form of a technology, known as automatic identification and data capture (AIDC), which uses radio frequency signals to transmit information. RFID is used to identify objects, animals and people in applications including agriculture, manufacturing and transportation; motor vehicles fitted with RFID tags, for example, can pass through highway tolls without stopping, reducing congestion.
History
The history of RFID can be traced back to World War II, when it was used by the British to identify enemy aircraft. The technology was first used commercially in the 1970s and 1980s and entered a new era in 1998, when researchers at the Massachusetts Institute of Technology started to investigate how objects could be identified and tracked using radio frequencies and how the information could be shared with business partners in real time.
Components
An RFID system consists of a tag or transponder -- a tiny silicon microchip, less than two hundredths of an inch across, attached to a small, flat aerial -- a reader or interrogator and a host computer. The RFID tag is attached to the object to be identified and contains a unique identification number, known as an Electronic Product Code. The reader sends and receives radio frequency signals to and from the tag and passes the data to the host computer, where it is processed into useful information by specialized RFID software.
Benefits
Radio frequency signals can penetrate many materials, so unlike optical AIDC technologies such as bar codes, RFID does not require direct line-of-sight between the tag and the reader. This means RFID tags can be read quickly, without the need for repositioning of the object to be identified. Furthermore, radio frequency signals can be received effectively over a distance of several yards under normal operating conditions.
Active and Passive Tags
An active RFID tag employs an internal battery to power its onboard circuitry and to communicate with the reader. Active RFID tags can communicate over longer distances than passive RFID tags, but are physically larger and more expensive. A passive RFID tag has no power supply of its own and relies on the energy of the transmissions it receives from the reader for communication. It has a limited operating range compared with an active RFID tag, but is correspondingly smaller, lighter and cheaper; depending on the precise application, the physical size and weight of the tag can be highly significant.
Tags: frequency signals, RFID tags, active RFID, host computer, object identified