RFID Basics

UPM RFID tags and inlays

WHAT IS RFID?
RFID stands for Radio Frequency Identification. RFID is a technology used to identify, track and trace objects. Tagged items, such as parcels, jewelry, groceries or clothes, can be identified via radio waves with special RFID readers.

RFID has its roots in the Second World War. Originally, it was used to identify aeroplanes. Now RFID is widely used by the private sector and consumers. The first consumer applications using RFID were anti-theft and access control systems.

RFID TAG
Most RFID tags contain at least two parts. One is an integrated circuit (IC, microchip) for storing and processing information, modulating and demodulating a radio-frequency (RF) signal, and other specialized functions. The second is an antenna for receiving and transmitting the signal.

RFID SYSTEM
An RFID system is comprised of:

  • a tag
  • the reader (an interrogator)
  • a host system (computer)
An RFID reader acts like a radio by picking up signals. It reads and writes information to and from the RFID tags or inlays. The host computer manages the information flow, sending to and receiving from the reader and tag. The data flow between the reader and tag occurs over an air interface, or radio frequency (RF) link.

HF AND UHF
RFID tags and readers act like radios which have their own, very specific stations. These ‘stations’ talk to each other mostly using either HF (High Frequency) or UHF (Ultra-High Frequency) signals.

High Frequency (HF) tags
  • have a read range of up to 1 meter/3 feet and can be read even when other HF RFID tags are touching them
  • are insensitive to the presence of water
  • are ideal for library, mass transit and product authentication RFID applications
Ultra-High Frequency (UHF) tags
  • have a read range of nearly 14 meters / 46 feet
  • are sensitive to liquids and metal
  • are ideal for transportation, distribution and shipping

PASSIVE, ACTIVE AND SEMI-PASSIVE RFID TAGS
RFID tags come in three types: passive, active and semi-passive. Most of the tags and inlays manufactured by UPM RFID are based on passive RFID technology. This means they don’t require an internal power supply or battery. The power required to energize the tag is drawn from the magnetic field created by the reader’s antenna.

Active and semi-passive RFID tags use internal batteries to power their internal circuits. The difference between these two is that an active RFID tag also uses its battery to broadcast radio waves to the reader. A semi-passive RFID tag relies on the reader to supply power for broadcasting.


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