What is the RFID card developed？RFID has been used and depended on for over 70 years. In 1945, Léon Theremin invented an espionage tool for the Soviet Union which retransmitted incident radio waves with audio information. Sound waves vibrated a diaphragm which slightly altered the shape of the resonator, which modulated the reflected radio frequency. Even though this device was a covert listening device, not an identification tag, it is considered to be a predecessor of RFID, because it was likewise passive, being energized and activated by waves from an outside source.
The first RFID-related device was invented by Mario Cardullo and patented on January 23, 1973, which was a passive radio transponder with memory. But, the earliest system that used the same concepts as an RFID system was first RFID card developed during World War 2. In order to identify themselves as friendly aircraft, British planes would have transmitters that would receive a signal from a ground based radar station and broadcast a friendly return signal in reply. On the other hand, the first patent to be associated with the abbreviation RFID was granted to Charles Walton in 1983.