RFID stands for radio frequency identification, and is a technology used to identify objects using radio frequency transmissions. The technology, itself, is not new -- it was first used to identify friendly aircraft during World War II -- but it is being applied in a variety of new ways. RFID chips can be fitted to cars to reduce traffic congestion at tollbooths on the highway, or even implanted into pets so they can be identified and returned to their owners if lost.
Components
The essential components of an RFID system are a transponder or tag, a reader and a host computer. An RFID tag is a small radio device, consisting of a silicon microchip, just a few hundredths of an inch across, and a small, flat aerial. The whole tag can be enclosed in plastic or some other material, depending on how and where it will be attached to an object.
Active & Passive Tags
RFID tags can be described as active or passive, depending on whether or not they have their own power supply. Active RFID tags are battery-powered, so the life span of the tag is effectively limited by the life of the battery. Active RFID tags are more expensive than passive RFID tags, but are capable of transmitting over distances of around 330 feet, or over 30 times further than passive RFID tags. Passive RFID tags, on the other hand, draw their power from the radio waves transmitted by the reader. They have a smaller memory capacity than active RFID tags and are capable of transmitting over distances of around 10 feet.
Reader
RFID readers consist of one or more antennae, which send and receive radio frequency transmissions to and from RFID tags. RFID readers can be fixed or portable and vary in size, weight and output power, depending on the specific application. An RFID reader acquires data from one or more RFID tags and passes it on to a host computer. The host computer, in turn, typically contains a database, which stores information about tagged objects, and so converts the acquired data into useful information for the end user.
Benefits
RFID works on the same basic principle as bar code technology, but instead of using light, RFID uses radio waves to read information from an RFID transponder or tag. This means no line of sight is required between the tag and the reader, so the tag can be hidden inside a container or, indeed, a pet, and still be read effectively.
Tags: RFID tags, host computer, radio frequency, Active RFID, Active RFID tags, around feet