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Radio waves were first predicted by the theory of electromagnetism that was proposed in 1867 by Scottish mathematical physicist James Clerk Maxwell. [6] His mathematical theory, now called Maxwell's equations, predicted that a coupled electric and magnetic field could travel through space as an "electromagnetic wave".
Radio waves are defined by the ITU as: "electromagnetic waves of frequencies arbitrarily lower than 3000 GHz, propagated in space without artificial guide". [5] At the high frequency end the radio spectrum is bounded by the infrared band. The boundary between radio waves and infrared waves is defined at different frequencies in different ...
For example, Hertz was able to focus the waves using a lens made of tree resin. In a later experiment, Hertz similarly produced and measured the properties of microwaves . These new types of waves paved the way for inventions such as the wireless telegraph and the radio .
In radio communication, used in radio and television broadcasting, cell phones, two-way radios, wireless networking, and satellite communication, among numerous other uses, radio waves are used to carry information across space from a transmitter to a receiver, by modulating the radio signal (impressing an information signal on the radio wave ...
HF's position in the electromagnetic spectrum.. High frequency (HF) is the ITU designation [1] [2] for the band of radio waves with frequency between 3 and 30 megahertz (MHz). It is also known as the decameter band or decameter wave as its wavelengths range from one to ten decameters (ten to one hundred meters).
Astronomers have detected one of the most distant and energetic mysterious fast radio bursts in space, a millisecond-long blast of radio waves that traveled 8 billion years to reach Earth.
Medical applications of radio frequency (RF) energy, in the form of electromagnetic waves (radio waves) or electrical currents, have existed for over 125 years, [9] and now include diathermy, hyperthermy treatment of cancer, electrosurgery scalpels used to cut and cauterize in operations, and radiofrequency ablation. [10]
A new type of stellar object has been discovered releasing energetic bursts of radio waves every 22 minutes. An unusual object has been releasing pulses of radio waves in space for decades ...