D3.7 A Structured Collection on Information and Literature on Technological and Usability Aspects of Radio Frequency Identification (RFID)

Untitled TAGS

RFID tags are essentially radio transponders, i.e. they can receive and transmit using radio waves. Whilst all RFID tags at the basic level are used to store and transmit data, the variations in RFID tags are mainly due to their specific application. The application may dictate that the tag has to be readable over a certain range, and that will in turn dictate the technology just to transmit data and the amount of data it can store. These factors have a further bearing on the form factor (i.e. shape and size) of the tags themselves. Typically the most decisive element of the tag is the aerial – greater reading range will generally require an aerial with a larger surface area. With applications such as smart cards, a large flat area exists which can house a suitable aerial. However, in other applications such as RFID tags used for medical identification, the size is of importance and as such the useable range is limited. In some cases this is a desirable feature which helps in increase the security of the device. 

In case readers cannot receive the signals of tags e.g. placed on various products on a palette, repeater tags can be used. These tags simply act as a kind of proxy. They are powered with a battery and are able to receive and resend signals from other tags. Using repeater tags shielding can be circumvented and weak signals of tags in farer distances can be amplified.