In the military it is essential to identify who is friend and who is foe when at war. Uniforms, flags and banners were used for centuries to distinguish cohorts from others. However, in darkness these visual aids were useless. In World War II, with the widespread of military aircraft a change in identifying opponents was needed. At first a technology was made where the military could identify, using powerful pulses of radio energy and detecting the echoes that were sent back, on coming aircraft. Issues quickly arose due to the fact that this technology didn’t allow for them to distinguish who was approaching. A historical example of this is the event known as Pearl Harbor. The US radar station at Diamond Head detected incoming armada, but it was dismissed as American aircraft from the mainland. Due to this mix up, the Identification Friend or Foe (IFF) device was made.
IFF is a primary means of aircraft identification in Air Defense operations. This procedure quickly identifies aircraft as either enemy aircraft or friendly aircraft in order to implement rapid engagement or to conserve air defense teams. The IFF transponder was invented in the United Kingdom in 1939 and is still being used by aircrafts today.
In 1946 a Russian engineer by the name of Leon Theremin created a tool for espionage. It used a low power infrared beam to pick up vibrations in glass far away. If people spoke clearly, this device would pick up everything they would say. This system modulated the reflected radio frequency.
These two devices along with Mario Cardullo’s U.S. Patent 3,713,148 in 1973 where the building blocks of RFID used today.
