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Definition: microwave


Meaning "small wave," a microwave is a radio signal in the frequency range from 300 MHz to 300 GHz or from 1 to 300 GHz, depending on the rating system. Except for AM and FM radio, shortwave radio and over-the-air TV, almost all other communications systems transmit microwaves, including satellites, cellular systems, wireless LANs and line-of-sight between buildings and across vast distances.

Confusing Terminology
The microwave bands include the millimeter wave bands, which range from 30 to 300 GHz. See spectrum, millimeter wave and microwave oven.




Early Microwave Tower
Line-of-sight microwaves were first used to transmit across long distances where the terrain was too difficult to lay cable. This tower was installed in 1969 in Boulder Junction, Colorado. (Image courtesy of AT&T.)