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Developments in RFID

Dr. John Gill
22nd March 2006

Radio frequency identification has been used since the Second World War as a way of identifying aircraft for military purposes. This was just recognition of a pattern of frequencies, whereas current systems rely on digital data. Recent developments are dramatically reducing the price and so opening up a whole range of new applications.

A RFID tag contains an electronic chip and some form of aerial. A passive tag does not contain any power source, so has to rely on the power from the incoming signal. However an active tag contains a low voltage power supply (eg a small battery) either incorporated in the tag or within a related holder. An active tag can be read at a far greater range for a given transmitter power. Typically a passive tag can be read at distances of up to a few metres but active tags can have a range in excess of 100 metres.

A simple passive tag just contains memory that may be read-only or may be read-write. The former may be used as replacements for barcodes, but the latter are used when the information stored in the tag needs to be updated. A tag can also contain a microprocessor that gives the possibility of incorporating simple encryption of the data.

There are a limited number of radio frequencies licensed for use with RFID tags; these are:

  1. Low frequency (125-134 kHz) for applications where only a small quantity of information has to be read (eg animal tracking, car immobilisers). At these frequencies there is low absorption of the signal from liquids. However low frequency tags require relatively large aerials (order of centimetres) made of wire coils.
  2. High frequency (13.56 MHz) is used for contactless smart read systems such as for public transport ticketing. The speed of reading the data on the tag is much faster and the aerial can be incorporated within a standard size of a credit card (known as an ID-1 card size).
  3. Ultra high frequency (860-960 MHz) results in a shorter range but higher data transfer. It is anticipated that this will be the usual frequency for tags for goods in the supermarket. Also the unit cost of the tags is lower than ones which work at lower frequencies. This is partly because the aerials can be printed using conductive inks.
  4. Microwave frequency (2.45 GHz) can be used when there are no liquids in the immediate proximity of the tag (NB this is a similar frequency to that used by microwave ovens). This frequency band is used by many other devices including Bluetooth and WiFi.

Contactless smart cards have been in use for many years for public transport applications, but up to recently have been considered relatively insecure. So financial transaction cards have usually been contact cards. However the security aspects have improved to such a stage that Visa, MasterCard and American Express are all planning to deploy contactless cards in the foreseeable future.

RFID tags have also been used for some time in supply chain management (eg on pallets of goods for supermarkets) but the cost has prevented them from being used on the individual products. However the price is now coming down to a level where the cost can be justified on higher value items. For a retailer the main advantage of RFID over barcodes is that more information can be stored on the RFID tag (typically 96 compared with 13 characters). This means that it can hold information such as the 'sell by' date. Another potential advantage is that a whole trolley full of shopping can be 'read' without unloading the trolley.

An area that is likely to see early adoption of these tags is pharmaceutical packaging since it will help to alleviate the problem of counterfeit drugs.

RFID tags can be made with different memory capacities but the price will be significantly higher if it is a 'non-standard' size. With extra memory there is the possibility to store extra information. For instance, it could store a list of ingredients; this could be useful for someone with a nut allergy since a simple device could warn them of hazardous products.

Another possibility would be for the washing machine to incorporate a tag reader, and for the tags on clothes to include information about the washing temperature required; then the washing machine could automatically select the correct washing programme.

RFID tags are already used by some blind people to label their possessions (eg CDs), and they have a reader with speech output to help them select the correct item. However there are many more potential applications of benefit to people with disabilities. For instance active RFID tags could be used to label shops in a shopping centre or exhibits in a museum so that users could obtain audio information about exhibits in a choice of languages.

For all this to happen, it will require:

  1. The cost of tags to reduce to acceptable levels.
  2. Agreement on standards so that tags can be read by a range of terminals from different manufacturers. This will require agreement on how information should be stored on the tag.
  3. The business case for adding extra information that may only be needed by some customers with disabilities.
  4. Legislation or mandatory regulation when commercial organisations do not perceive a short-term financial benefit from providing these facilities.
  5. Disabled consumers articulating and quantifying their needs that could be addressed using RFID technology.

 



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