^History of EM waves
In 1865 Maxwell predicted the existence of electromagnetic waves purely from theoretical consideration. He showed that an accelerating charge produce EM waves of wave frequency as that of the oscillating charge.
In 1887, Hertz succeeded in experimentally confirming the existence of em waves. He sued an oscillatory LC circuit for producing these waves he was able to produce and detect e.m. waves of wavelength around 6 m.
In 1885 J.C. Bose succeeded in producing EM wave of much shorter wavelength (5 mm to 25 mm) with the help of a self designed radiator. He was able to transmit EM waves over a distance of about 20 m.
In 1896 Marconi, succeeded in transmitting EM waves across the British Channel in 1899 and across the Atlantic ocean in 1901. His experiments marked the beginning of radio communication.