Radio Frequency identification (RFID) basics

RFID or Radio Frequency identification is a technology that enables the tracking or identification of objects using IC based tags with an RF circuit and antenna, and RF readers that "read" and in some case modify the information stored in the IC memory.

The RF tags could be divided in two major groups:

Passive, where the power to energize the tag’s circuitry is draw from the reader generated field.

Active, in this case the tag has an internal power source, in general a battery that could be replaceable or not, in some case this feature limited the tag lifetime, but for some applications this is not important, or the tag is designed to live more than the typical time needed.

The RF tags could be seen at first sight an "improvement" of the bar codes used today almost everywhere. But they provide several key advantages over the classical optical systems:

1- Do not require line of sight.
2- Could store far more information than a printed bar code.
3- In some case are writable, so they could store data during its lifecycle.
4- Could have additional electronic that could sense environmental factors as temperature, humidity, light, pressure, etc.

In the following sections we will analyze in detail several aspects of RFID systems.

Passive tags

Active RFID tags

Frequency use

Uses of RFID technology

Access control

Retail & service industry

Transport & fleet management

Anti-counterfeiting devices

Libraries