Chips with everything - an RFID primer




Radio frequency identification (RFID) technology was first envisaged just after the Second World War, when transponders for aircraft were developed using a precursor of the technology, as outlined in The history of RFID. Today, thanks to advances in miniaturisation and radio communications, millions of RFID tags now litter our retail products, warehouses, medical institutions, and even our pockets. What are they, how can they be used, and how are they developing in line with future requirements?

Passive RFID

The most common type of RFID is known as a passive device. It requires an external electromagnetic source to activate. In a passive scenario, a reader provides enough power for passive fight the tag to transmit its data over a short distance. It is primarily used for applications in which a dormant item must be read infrequently, such as in retail, where tags on items of clothing may occasionally need to be queried.

There are many other applications for passive RFID.

Many concern themselves with tracking a unique identifier attached to a physical object. For example, passive or ID tags can help companies to trace items through the supply chain, ensuring that they are legitimate, and in the right place at the right time. This becomes particularly important in highly regulated applications with items prone to tampering, such as pharmaceuticals, for example.

Active RFID

Active RFID has a number of differences compared to passive RFID. It contains a battery, allowing it to autonomously broadcast its signal, without waiting to be activated by an external reader. It also has a much longer range, of 100 metres or more, compared to the 3 metre range inherent in passive RFID tags. Generally, active RFID will contain more data, and will cost somewhere in the region of 50 times the price of a passive tag.

The benefit of active RFID tags is that they can be used within a large designated area, such as a warehouse, or a road toll system. Conversely, the shorter range of passive RFID tags makes them more suitable for scanning very narrow areas through which high volumes of goods will pass (such as a retail point of sale system).

Because of its broader range, active RFID has significant potential in enterprise applications such as ERP, where supply chains must be monitored in environments that cannot be very closely scan. One example might be shipping containers, which might be scanned from a dock while they are sitting on a boat.

Machine to machine (M2M) applications can be used to automatically scan active RFID tags in such environments, feeding the data through to ERP software applications that can use it to update product and material workflows. For example, a container of chilled food might log its temperature constantly on an active RFID sensor, which might communicate its logs to an M2M application when it hits the port. This could relay the history to an ERP application, which might automatically adjust the scheduling of the food on retail shelves based on the data. ERP applications such as SAP and Oracle support RFID, but commentators suggest that some middleware customisation may be necessary to make it work seamlessly.

NFC and mobile phones

Based on RFID, Near Field Communication (NFC), as promoted by the NFC Forum, is a two-way communication technology that works over much shorter distances, measured in centimetres rather than metres. Consequently, it is referred to as a contactless technology, which generally requires one device to be touched to another (or at least waved very close) for a data transaction to be completed.

One area of NFC that is beginning to open up is low value transactions. MasterCard operates a system called PayPass, in which a card preloaded with plants can be tapped against the reader to pay for groceries, and other items. Visa has a similar system called payWave.

Oyster card, designed to store credits for use on the London public transport system, also uses NFC technology. Users charge up the card by paying at a kiosk, and then touch the card against a reader when they want to begin a trip. The card is then debited to reflect the payment.

The ultimate logical conclusion for NFC technology is to put it directly into mobile phones, which are becoming hubs for general day-to-day interaction with social networks and consumer services. Instead of touching a card to pay for a low value item or gain paid admission to a service, users will be able to touch their phones to a reader instead.

Projects supporting this idea are already underway. For example, Orange conducted a trial with Reading Borough Council in the UK in late 2008, enabling members of the public to pay for past services using a Sony Ericsson mobile phone with an NFC chip and a SIM card to authorise payment.


However convenient NFC technology may turn out to be, there are also significant security implications. In June 2008, Dutch academics developed a technique to clone an access card using the Mifare chip, which forms the basis for the Oyster card, among many other smartcards.

Other security problems have been discovered with RFID. For example, Adam Laurie, a researcher specialising in RFID security, demonstrated how to clone the UK's recently introduced biometric passport in 2007. He managed to guess a key, printed inside the passport, which is meant to give access to the encrypted data on the RFID chip. They key was not created randomly, and he could guess it using specific facts about the recipient of the passport. He then used the key to read the chip from a demonstration passport which was still inside a sealed envelope, as it would be sent in the mail. This would then enable him to clone the passport.

Cost and reliability

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The manufacturing cost of passive RFID tags is far lower than their active counterparts, because of the simple components, and the lack of a battery. As large retailers including Wal-Mart mandate the use of such tags, it is hoped that the economies of scale will continue to bring down costs. Reliability problems, which were an issue with some of the earlier RFID tags, are now being resolved thanks to better technology. It is becoming easier to read these tags when they are positioned on and around lots of metal objects such as clothes hangers, for example.


Perhaps the biggest barrier to the take-up of RFID is the lack of standardisation. There is no single body governing a global standardisation movement, although EPCGlobal, an organisation set up to standardise electronic product code techniques, is currently the main contender. EPCglobal created the EPC Gen2 standard, focusing on passive RFID, and designed to bring the cacophony of different protocols underpinning the medium together.

Anthony Plewes

After a Masters in Computer Science, I decided that I preferred writing about IT rather than programming. My 20-year writing career has taken me to Hong Kong and London where I've edited and written for IT, business and electronics publications. In 2002 I co-founded Futurity Media with Stewart Baines where I continue to write about a range of topics such as unified communications, cloud computing and enterprise applications.