An RFID antenna consists of a coil with one or more windings and a matching network. It radiates the electromagnetic waves generated by the reader, and receives the RF signals from the transponder.
An RFID system can be designed so that the electromagnetic field is constantly generated, or activated by a sensor.
Antennas also come in different sizes and designs, this depending very much on the environment into which a system is integrated. The required read and write range also play a role.
Common forms are rod or loop antennas. For greater reading range or different orientations of a transponder, a number of antennas can be arranged in one reader unit.
