Introduction

Radio Frequency Identification (RFID) is a general term that is used to describe a system that transmits the identity (in the form of a unique serial number) of an object wirelessly, using radio waves. RFID is evolving as a major technology enabler for tracking goods and assets around the world. A great deal of attention is being paid to RFID by the IT industry, media and analysts. According to studies by Benchmark Research, in 2004 three quarters of manufacturing companies are now aware of RFID, of which a third are already using, piloting or investigating RFID applications for their organisations.

Anticipating the potential benefits of RFID, many of the world’s major retailers are trialling RFID tagging for pallets and cases shipped into and out of their distribution centres. The consequence of this RFID activity in the retail sector is likely to impact on around 200,000 manufacturers and suppliers globally, and will fuel the market for hardware and software to support RFID.

RFID has many applications outside of the retail supply chain including many familiar ones such as vehicle security, commuter tags and security badges for access control into buildings.

The Development of RFID

Over the years methods for capturing and storing information have evolved from paper and card systems, through keyboard data entry, bar code data capture and are now augmented by technological improvements such as touch screens on the shop floor. All of these initiatives have been aimed at improving accuracy, completeness and timeliness of information. However these all rely on access to a host computer system to make use of data collected.

So, how does RFID differ from other methods of identification and data capture? A typical RFID system is made up of three components: tags, readers and the host computer system.

Tags - An RFID tag is a tiny radio device that is also referred to as a transponder, smart tag, smart label or radio barcode. The tag comprises a simple silicon microchip (typically less than half a millimetre in size) attached to a small flat aerial and mounted on a substrate. The whole device can then be encapsulated in different materials (such as plastic) dependent upon its intended usage. The finished tag can be attached to an object, typically an item, box or pallet and read remotely to ascertain its identity, position or state.

Readers – The reader, sometimes called an interrogator or scanner, sends and receives RF data to and from the tag via antennae.

A reader may have multiple antennae that are responsible for sending and receiving radio waves. The readers can be fixed or mobile, can read information stored on the tags and write information to them. This can be achieved without direct line of sight and in environments where traditional data collection could not operate. A major advantage is that information can be written to the tag multiple times so storing a history that travels with the article.

Host Computer – The data acquired by the readers is then passed to a host computer, which may run specialist RFID software or middleware to filter the data and route it to the correct application, to be processed into useful information.

RFID is not a new technology, in fact it was first used by the US military during WWII, but wider deployment chain was slow due to the high costs of equipment and its limited reliability in volume environments. RFID equipment has steadily fallen in price as volumes increase and microchip unit production costs fall. With the ability to store several kilobytes of data in addition to the ‘number plate’ identifier it could be viewed as a form of ‘mass distributed database’ that has the potential to become ubiquitous - billions of tags in daily use throughout the world on all objects that are produced, stored, moved, sold and maintained.

Automatic Identification

RFID technologies are grouped under the more generic Automatic Identification (Auto-ID) technologies. Examples of other Auto-ID technologies include Smartcards and Barcodes. RFID is often positioned as next generation barcoding because of its obvious advantages over barcodes. However, in many environments it is likely to co-exist with the barcode for a long time. The barcode labels that triggered a revolution in identification systems back in the 1970’s are now cheap and commonly used, but have several limitations:

• low storage capacity
• they only represent a family of items and not an individual or unique item
• durability (as mostly printed paper)
• low read range
• they can only be read when line of sight is established
• they can only be read one at a time
• they cannot be written to or reprogrammed

Rather than using light to collect or read a number from a bar code, radio waves are used to read a number from the RFID tag. RFID therefore does not need line-of-sight to operate. Using radio means that the tag no longer has to be visible on the object to which it is attached; the tag can be hidden inside the item or box that is to be identified and still be read. This minimises or eliminates the need for a person to have to present the reader to the tag as it can now be fixed to a wall for example. As the item is passed by the reader it will be read automatically, thus giving a potentially large saving in labour costs or substantial increase in throughput of scanned items.

Another feature of RFID is the ability to read many tags together at once. It is not necessary to present each tag to the reader separately (as is required for barcodes), instead all tags within the range of the reader can be read almost simultaneously as they pass the reader. Again, there is a huge savings potential in not having to manually present the reader to each item to be identified.

Applications for RFID

Applications fall into two principal categories: firstly, short range applications where the reader and tag must be in close proximity (such as in access control) and secondly, medium to long application, where the distance may be greater (such as reading across a distribution centre dock door). Examples include:

RFID in the UK Supply Chain

An example of one of the earliest retail supply chain trials was between Marks and Spencer and some of their key suppliers. The RFID tags are attached to trays of products and suppliers pass the trays through a writer situated at the end of their production lines. The writer stores order, product and batch details on the tag and as the trays pass through the transport chain they are automatically read as they pass through gateways so the M&S system is kept up to date with the location and status of goods. When the trays are emptied they return to the suppliers where they are re-used and the tags rewritten.