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Radio frequency identification (RFID) tags are devices containing information that can be transmitted to a reader to verify authenticity, to control inventory, or to control access to virtual or physical space. RFID tags can combine a unique identifier such as a serial or batch number with data on the physical environment such as temperature or shock collected by sensors integrated into the device, thereby preventing spoilage or malfunction. RFID tags are designed to transfer and store data in several ways; e.g. read-only, read-write or read-wipe. The transmission technology determines how close the device needs to be to a reader. Contactless devices such as financial transaction or access control devices work at a range of 1 cm and require conscious submission of the device for scanning. Unconscious identification is possible at distances as far as 1-2 meters for transactions such as passport, visa or staff access authorizations while moving though a checkpoint.
Additional functionality in RFID tags requires an increase in the power requirements. Typical RFID tags used today are passive and require no power storage since the power required to transmit the signal over a very limited distance is generated inductively while the tag is in the proximity of the reader. Newer generations of active tags require battery power to maintain the ongoing data collection required by sensors or to power an on-board clock. RFID tags that can communicate several different sets of data to specific readers are under development and will require small and reliable batteries to support these functions.
RFID applications in transportation include systems for vehicle fleet management, location of trains and train cars or electronic tollbooths. Other RFID solutions include livestock husbandry, luggage verification at airlines, automated ski lifts or industrial laundries. The European Central Bank is working to embed radio frequency identification tags into the fibers of Euro bank notes by 2005.
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