Radio frequency identification uses radio-sensitive tags, which can store data and be read at a distance, to identify objects such as people, animals, merchandise, vehicles and baggage.

RFID smart tags consist of a small silicon chip (usually 20cm square), an aerial and some packaging.

They can be packaged into almost anything - paper label, a piece of plastic or even a plastic crate.

The circuitry on the chip includes an element that makes it react to a signal received by the aerial, some processing power, storage capacity and circuitry to enable it to transmit a signal to a reader.

An RFID reader can activate a smart tag from a short distance - a few centimetres to a few metres depending on the frequency and power of the tag. It can request information and it can also store more information.A reader can process a large number of smart labels in a very short time.Usually the limitations are the size of the reading area or the mechanical speed of a conveyor.As it is all based on radio waves from sealed units, the system does not need line of sight and is not susceptible to moisture, dirt or chemicals.