The first name, however, that bags credit is Guglielmo Marconi. He was the first person to successfully apply the theories of wireless technology. In 1895, he sent out the first radio signal, which consisted of the single letter 'S'. With this, he was granted the world's first patent for the radio. However, with time, it was proved that many theories used in the making of a radio were actually first patented by Nikola Tesla. Therefore, in 1943, the government authorized the patent for the radio invention to Tesla.