Whereas a barcode appears printed externally on the object to be scanned, an RFID tag can be embedded within the object itself, or even within a living body – as in the injectable tags which are used for pet identification. The setup for an RFID configuration consists of a scanning antenna which emits radio-frequency radiation, and the tag which is essentially a transponder programmed with the item’s information. The use of the radio frequency radiation not only allows the communication between the devices but can also supply the RFID transponder with a source of energy, meaning that RFID tags do not necessarily need to contain a battery. These tags are called ‘passive’ RFID tags, and as a result have a long life expectancy. On average an RFID tag can carry up to 2000 bytes of data. In essence there is no difference between the purposes of RFID tags and barcodes – each simply provides a unique identifier for a certain product or object.
‘Active’ RFID tags contain their own power source or batteries, meaning that these tags can be scanned at a larger distance, even at several meters away, and still generally have a lifespan of around a decade. High frequency devices are capable of reading tags as far as 20 feet from the scanner. Currently RFID tags are widely used in the automobile production and pharmaceutical industries, as well as for livestock tracking. The technology actually dates back over 50 years. It is only recently however that the costs of producing the various electronic components has fallen low enough for RFID to pose a viable alternative to ‘disposable’ barcodes. Because of this there has been no real motivation for industry standards to be implemented on a broader scale and for the system to become more widely adopted. Most companies using RFID tags do so internally only, to track their own inventory.
Issues with RFID technology:
Because RFID technology is designed for very high scanning speeds, issues of “tag collision” and “reader collision” can occur. This happens when signals from multiple readers overlap and the tag is unable to respond to the simultaneous reader queries. Tag collision likewise occurs when many tags are present in a small area and the reader is unable to separate the various return signals.
Cellphone and WiFi networks which also make use of the electromagnetic spectrum can also create ‘jams’, which whilst not much more than an inconvenience in a retail scenario, could be a very serious problem in the medical industry or high-security situations, where energy at the correct frequency could potentially be used to create deliberate interruptions. In the case of Active RFID’s which depend on their own batteries, a system set up to repeatedly query the tag could be used to wear the battery down.
Privacy and ethical concerns:
Normal RFID tags cannot be made unreadable after you leave the shop where you have purchased your items, and RFID readers are relatively portable, and can read tags from a considerable distance. This raises concerns that anyone with an RFID reader will be able to scan all the items you have on your person, potentially making you a walking target for thieves. The use of so-called ‘Zombie’ tags which can be de-activated upon checkout has been suggested, but again this adds to the overall cost of the technology.
The concept of extending this technology to human implants has naturally triggered some controversy and privacy concerns. Improvements in RFID printing methods and the tiny size of the tags themselves – some less than 0.5mm2 – means that high-frequency antennas would be able to scan all the items on a person without their knowledge.
Advantages of RFID tagging vs traditional barcodes:
RFID tags have a few key advantages over traditional barcode systems – mainly the read rates of multiple items, and the fact that no direct line of sight needs to exist between the object and the tag – the tag can be embedded within the product itself. This also means that the durability of the tag is increased because it does not need to be exposed on the outside of packaging.
In addition, data in an RFID tag can be rewriteable if the tag has been designed for this. The new technology means that whereas each item in a shop has been assigned a product barcode, a unique identifier for that type of merchandise – it may now be possible for each separate item of stock to have a unique identifier, which could be linked to the bank card with which the purchase was made. This could be an invaluable tool in police investigations and forensics.
However all of these benefits of course come at a price, and it is unlikely that we will see widespread retail use for quite some time. Standardisation of RFID systems is still also in its infancy, and like the global implementation of retail barcodes it will be many years before we see large-scale adoption and standardisation.