What is RFID?

RFID, or Radio Frequency Identification, is an emerging technology used for identification of items. It is already used in many applications, ranging from security passes to easy payment on toll roads. In supply chain management, RFID represents the next step beyond bar codes. Like bar codes, RFID tags identify products to a retailer. Unlike bar codes, RFID enables suppliers to track every individual item in their supply chain; bar codes only allow the tracking of item categories. For example, with bar codes, a retailer might know that they have 10 pallets of bubble gum in their warehouse. With RFID, the retailer can know specific details of each package of gum, such as what factory it's from, how old it is, and where it needs to be shipped. The retailer can use this additional information to significantly reduce costs, usually due to reductions in inventory, stock-outs, and shrinkage. Symbol Technologies, a producer of both bar code and RFID systems, estimates that RFID can save U.S. retailers $300 B in supply chain inefficiencies and inventory.

Advantages of RFID

With RFID, it is possible to track inventory flows in real-time. This provides a clear, accurate, easy to obtain picture of your supply chain.

Unlike bar codes, RFID tags can contain individual product identification, allowing the tracking of data such as expiration, warranty and service history. In addition RFID tags can be read and re-written many times Ð allowing information to be dynamically updated. Another advantage of RFID is that it is not limited to 'line of sight' and has a much greater range than bar code readers.

History of RFID

RFID was developed in the 70's and has been implemented across multiple industries on products ranging from cattle to consumer goods. Until recently, readers and tags from different manufactures worked on different radio frequencies and contained different types of information, making products from different manufacturers incompatible. At the turn of the millennium, a group of manufacturers and universities formed a consortium to effort the standardization of RFID. This group, named Auto-ID, developed standards for radio frequency band usage, format of IDs (labeled 'EPC'), and software management. Auto-ID has since disbanded, but was replaced by EPCglobal, a consortium of several companies and standards organizations. EPCglobal is the current creator and maintainer of RFID standards.

How Does RFID Work?

RFID works by manipulating radio frequencies and measuring this manipulation in order to form an ID. RFID uses a variety of frequencies for different purposes. A low frequency (125 KHz) transmission often is used on livestock tags and has good propagation at short ranges, but it has a relatively slow data transfer rate and a higher cost. High frequency (13.56 MHz) has reasonable propagation, faster data transfer and costs less, and it is the only frequency that can be used around the world. Ultrahigh frequency (860 MHz to 960 MHz, 2.5 GHz and 5.9 GHz) allows for rapid data transfer and costs little, but tags may obscure or interfere with each other. Both Wal-Mart and the DOD have cited their intent to use ultra high frequency RFID.

RFID tags come in three varieties (passive, active, and semi-passive). Passive tags do not have a power source - they rebroadcast a modified signal using power from the incoming radio signal. Passive tags have a limited number of read/write operations and a limited range. Active tags have an onboard power source that can power the integrated circuit (IC) chip and transmitter. Active tags have much more range than passive tags as well as a larger memory. Semi-passive tags are battery assisted - the IC is powered, but the antenna is not.

RFID infrastructure requires at least two pieces of hardware; the reader/scanner, and the RFID tag. Most sophisticated RFID systems will also require a third component; a software system capable of processing and filtering RFID tag data, such as logicAlloy's ALE Server.