RFID (Radio Frequency Identification) uses electromagnetic fields to automatically identify and track tags attached to objects. An RFID system consists of a tiny radio transponder (a device that emits a signal in response to a signal that it has received, also referred to as the “tag”), a radio receiver, and a transmitter( a device that produces radio waves with an antenna).

When triggered by an electromagnetic interrogation pulse from a nearby RFID reader, the tag transmits digital data back to the reader. This data can be whatever information the user wishes to insert on the tag.

Usually, this information comes in the form of inventory tracking numbers for products, identification of individuals in the form of access cards or tags, tracking of products during logistics, identification of animals in the form of RFID chips and many more uses.

There are two different RFID tags possible. Either they are active, meaning they have their own power source or they are passive. Passive tags do not have their own power source and have to be supplied with energy via an electromagnetic field produced by the reader.

Passive transponders or tags are available in three different RFID frequency ranges: Low frequency (LF), high frequency (HF) and ultra high frequency (UHF). The reading range of LF and HF systems is usually only a few centimeters. UHF tags, however, are often readable over distances of more than one meter.