After Niagara Falls, Tesla went back to experimentation. His new goal consisted of high frequency currents, which he believed could be used to wirelessly power household appliances at a much higher efficiency. He started by making larger AC rotary generators to achieve a high voltage, but every time he got close to twenty thousand cycles per second, his generators would rip themselves apart. This led to another very popular invention, the Tesla coil (patented in 1891). By using the tesla coil, Tesla could take standard household currents and speed them up to very high frequencies. These high frequencies allowed Tesla to invent neon lights, the first x-ray photographs, and most importantly, the wireless transmission of energy.
    Tesla realized that he could emit and receive high frequency radio waves if both the emitter and receiver were tuned to the same resonant frequencies. In early 1895, just before Tesla was ready to test his new invention by sending radio waves 50 miles, his building caught fire and burned all of his work. To make matters worse, an Italian physicist Guglielmo Marconi coined the first wireless telegraphy patent in 1896. "His device had only a two-circuit system, which some said could not transmit "across a pond." ” [01] Tesla bounced back and filed his own radio patent in 1897, which was granted in 1900. Shortly after, Marconi sent in his own radio patent on November 10th, 1900, but was repeatedly turned down. . .

The Patent Office made the following comment in 1903:

“Many of the claims are not patentable over Tesla patent numbers 645,576 and 649,621, of record, the amendment to overcome said references as well as Marconi's pretended ignorance of the nature of a "Tesla oscillator" being little short of absurd... the term "Tesla oscillator" has become a household word on both continents [Europe and North America].” [01]

    In 1904, the U.S. Patent Office surprisingly reversed it's previous decision and accepted Marconi's patent for the invention of the radio. Many people think this was a corrupt decision that was financially backed by

Marconi's company. This would eventually lead to Marconi winning the 1911 Nobel Prize, which made Tesla furious. Tesla tried suing Marconi's company in 1915 for infringement. Unfortunately, Tesla did not have the

money necessary to compete against a large corporation and lost the battle. In 1943, a few months after Tesla's death, the U.S. Supreme Court upheld Tesla's radio patent and restored his position as the inventor of radio.

                                           

Marconi with early system of radio transmission                         Tesla demonstrates wireless power transmission, May 1899                              Tesla's apparatus for wireless transmission of electrical energy
                                                                                                                                                                                                                                U.S. Patent 649,621 Patented May 15, 1900
                                                                                                                                                                                                                     Still the fundamental means for transmitting and recieving radio waves.