What is RFID tag?

RFID tags are devices used for Radio-frequency identification (RFID). RFID is the process or method of automatically identifying radio frequencies. The RFID tag consists of mainly a microchip that is combined with an antenna or coil. The antenna picks up signals from an RFID reader and then returns the signal with additional information. The chip or integrated circuit is used to store the information that is collected from the signals picked up. The chip can also be used to process this information or to modulate and demodulate the tracked signal. However, some RFID tags are chipless. This means that it does not make use of any integrated circuit to store information. The RFID tag instead uses fiber or materials that reflect a portion of the reader's signal back; the unique return signal can be used as an identifier. Its advantage over traditional RFID tags is that they can be used in several different environments and are also less sensitive to temperature changes and radio frequency interference.

The size of the RFID tag can vary. It can be very small like a grain of sand or large enough to compare with a small book. The RFID tag can be applied to a product, an animal or a human being for the purposes of identification. It does this by tracking the information needed using radio waves and thus can be read from a long distance off even when there is no direct line of sight. RFID data can therefore be read through the human body, clothing and non-metallic materials.

RFID tags can either be active, passive or semi-passive. Active RFID tags require an internal power source to power the integrated circuit and then broadcast the response signal to the reader. The power source can be a replaceable battery or a sealed unit or can be connected to an external power source. Passive RFID tags on the other hand do not contain an internal power source. When radio waves are encountered, an electrical current is induced in the antenna to form a magnetic field. This power is what is used to power up the passive RFID tag. Semi-passive RFID tags have their own internal power source which powers the chip but not the broadcasting of the signal. The response is powered when the energy is reflected back to the reader.

Uses of RFID tags

Tracking animals such as cattle.
Collection and storage of vital information about people.
Asset tracking for example in libraries, pharmacies and entertainment venues. Companies such as Michelin and Wal-Mart are also making use of the RFID tag. Michelin is using the RFID tag in their tires to make the tires easier to track. The tag stores the tires unique ID, information about when and where the tire was made, its maximum inflation pressure, size and so on.
Contactless payments. Customers can use their phones or a special keychain to make payments. An example of this is Speedpass.
Ticketing, gaming or payphone applications.
RFID tags have also been used for controlling car traffic, preventing kidnapping, tracking fashion, delivering orders in restaurants, toll and subway passcards, preventing surgical errors and several other uses.

Advantages of RFID tags

No need for contact to operate.
Does not require line of sight for communication.
RFID tags can be read through a variety of substances such as the human body, snow, fog, ice, paint, and other conditions where barcodes would be useless.
Fast processing even in challenging circumstances.
It can be read at distances of 100 feet or more.