RFID technology works on radio frequency and is used for automatic identification of various objects. The RFID system mainly consists of two parts.
1) RFID reader
The RFID reader continuously sends radio waves at a certain frequency. If the object to which this RFID tag is attached is within the range of these radio waves, it sends the feedback to this RFID reader. Thanks to this feedback, the RFID reader identifies the object.
2) RFID tags
Three different types of RFID tags are available for the commercial network: passive tags; active tags and semi-passive tags
Passive tags have no power. They get their power from incoming radio waves from the readers. While active tags have a power source for their internal circuitry that also serves to send the response to the reader. In the case of semi-passive tags, they have power for internal circuits, but rely on radio waves received by the reader to send a response.