A Radio Frequency Identification (RFID) tag is an electronic device that holds data. Typically these tags are attached to an item and contain a serial number or other data associated with that item. We will focus on passive RFID technology, in which the tag carries no power source, but is instead powered by a radio signal from a separate RFID reader.More recently, RFID systems have begun to find greater use in automatic identification applications. RFID systems consist of Radio Frequency (RF) tags, or transponders, and RF tag readers, or transceivers. The transponders themselves typically consist of integrated circuits connected to an antenna.