An RFID (Radio-Frequency IDentification) tag consists of a small silicon microchip attached to an antenna. The chip itself can be as small as half a millimeter square – roughly the size of a tiny seed. Some RFID tags are thin enough to be embedded in paper. An RFID tag is capable of transmitting a unique serial number a distance of up several meters in response to a query from a reading device. Inexpensive RFID tags are passive, meaning that they lack batteries and obtain their power from the query signal of a reading device itself.
RFID tags are already quite common in everyday life. Examples include proximity cards used as replacements for metal door keys, Speedpass™, E-Z Pass™ and FasTrak™ automated toll payment devices. Tens of millions of pets around the world have surgically embedded RFID tags that make it easy to identify them should they lose their collars.
Dropping cost is bringing RFID to the fore. In the near future, some RFID tags may cost as little as $0.05-0.10 in large quantities. We are rapidly approaching a critical turning point at which inexpensive RFID tags are viable as a cost-saving replacement for barcodes, of which some 5 billion are scanned around the world every day. EPCGlobal Inc. is perhaps the most important organization leading the standardization of RFID. Not surprisingly, it is a joint venture of the UCC and EAN, the entities that oversee barcode use in the U.S. and Europe.
RFID tags have two distinct advantages over traditional, printed barcodes:
- An RFID tag carries a unique identifier, whereas a barcode merely indicates an object type. For example, a barcode printed on a box might state that the box contains breakfast cereal, and also indicate the manufacturer. An RFID tag would effectively carry a serial number distinguishing that box of cereal from every other one in the world. This permits very fine-grained and accurate control over product distribution. With a full history for every item, businesses can streamline their manufacturing and distribution processes in unprecedented ways.
- An RFID tag may be read by radio contact, without the need for line-of-sight contact. In many cases, it can even be read through objects. A barcode scanner must make close-range optical contact to read a barcode effectively. In contrast, an RFID tag may be read without any real constraint on physical orientation. While an item in a supermarket must be passed over a scanner with its barcode expressly exposed, an RFID tag may be scanned just by being placed in the vicinity of a reader. Indeed, a reader is typically capable of scanning hundreds of RFID tags simultaneously. Again, this means extra efficiency and perhaps accuracy in the handling of items.
Wal-mart® and the U.S. Department of Defense have mandated that their top suppliers deploy RFID within the next couple of years. Their main interest is in tracking pallets or crates containing many items, rather than to tag items individually. By providing accurate, real-time inventory data, RFID has the potential to enhance supply-chain efficiency and reduce costs. In general, item-level tagging of consumer goods is unlikely to occur for some years.