Microwave

Microwave is a form of <a href="/facts/Electromagnetic_radiation/Ynx7ujCW">electromagnetic radiation</a> with <a href="/facts/Wavelength/kcJU0ymz">wavelengths</a> shorter than other <a href="/facts/Radio_wave/XmB6WPpF">radio waves</a> but longer than <a href="/facts/Infrared/44XdJNcc">infrared</a> waves. Its wavelength ranges from about one meter to one millimeter, corresponding to <a href="/facts/Frequency/QUSbPaW8">frequencies</a> between 300 MHz and 300 GHz, broadly construed.: 3 [excessive citations] A more common definition in <a href="/facts/Radio-frequency_engineering/fpFFb036">radio-frequency engineering</a> is the range between 1 and 100 GHz (wavelengths between 30 cm and 3 mm),: 3  or between 1 and 3000 GHz (30 cm and 0.1 mm).
The <a href="/facts/Prefix/C4Lw8npg">prefix</a> micro- in microwave is not meant to suggest a wavelength in the <a href="/facts/Micrometre/7eDFxD2L">micrometer</a> range; rather, it indicates that microwaves are small (having shorter wavelengths), compared to the <a href="/facts/Radio_wave/XmB6WPpF">radio waves</a> used in prior <a href="/facts/Radio_technology/XFr909M2">radio technology</a>.
The boundaries between <a href="/facts/Far_infrared/rlup3DSX">far infrared</a>, <a href="/facts/Terahertz_radiation/729QecPK">terahertz radiation</a>, microwaves, and <a href="/facts/Ultra-high-frequency/S6XDUaDY">ultra-high-frequency</a> (UHF) are fairly arbitrary and are used variously between different fields of study.
In all cases, microwaves include the entire <a href="/facts/Super_high_frequency/Bqrg4fcy">super high frequency (SHF)</a> band (3 to 30 GHz, or 10 to 1 cm) at minimum. A broader definition includes UHF and <a href="/facts/Extremely_high_frequency/l28Grdmp">extremely high frequency</a> (EHF) (<a href="/facts/Millimeter_wave/l28Grdmp">millimeter wave</a>; 30 to 300 GHz) bands as well.
Frequencies in the microwave range are often referred to by their <a href="/facts/Radio_band/AP2frA1C">IEEE radar band</a> designations: <a href="/facts/S_band/MF3nveB7">S</a>, <a href="/facts/C_band_(IEEE)/vLddLTc2">C</a>, <a href="/facts/X_band/eMpD5T2r">X</a>, <a href="/facts/Ku_band/czTuuqpT">Ku</a>, <a href="/facts/K_band_(IEEE)/EgQjtNNL">K</a>, or <a href="/facts/Ka_band/YqDrokxy">Ka band</a>, or by similar NATO or EU designations.
Microwaves travel by <a href="/facts/Line-of-sight_propagation/w4xfQd2o">line-of-sight</a>; unlike lower frequency <a href="/facts/Radio_waves/XmB6WPpF">radio waves</a>, they do not diffract around hills, follow the Earth's surface as <a href="/facts/Ground_wave/YexYxuur">ground waves</a>, or reflect from the <a href="/facts/Ionosphere/mT9tTBE5">ionosphere</a>, so terrestrial microwave communication links are limited by the visual horizon to about 40 miles (64 km). At the high end of the band, they are absorbed by gases in the atmosphere, limiting practical communication distances to around a kilometer.
Microwaves are widely used in modern technology, for example in <a href="/facts/Point-to-point_(telecommunications)/RmGgN1Pj">point-to-point</a> communication links, <a href="/facts/Wireless_network/yr4SWTdl">wireless networks</a>, <a href="/facts/Microwave_radio_relay/bz9H9Ete">microwave radio relay</a> networks, <a href="/facts/Radar/jk9BTbFA">radar</a>, <a href="/facts/Satellite_communication/y5RXPMDT">satellite and spacecraft communication</a>, medical <a href="/facts/Diathermy/aQFKbn55">diathermy</a> and cancer treatment, <a href="/facts/Remote_sensing/pj2crmGs">remote sensing</a>, <a href="/facts/Radio_astronomy/TdjF4LgL">radio astronomy</a>, <a href="/facts/Particle_accelerator/Pkuc08xC">particle accelerators</a>, <a href="/facts/Spectroscopy/mj71FuNK">spectroscopy</a>, industrial heating, <a href="/facts/Collision_avoidance_system/1xLggR3S">collision avoidance systems</a>, <a href="/facts/Garage_door_opener/WAkRXX0M">garage door openers</a> and <a href="/facts/Keyless_entry_system/tDLrF6WM">keyless entry systems</a>, and for cooking food in <a href="/facts/Microwave_oven/nS1B3wp2">microwave ovens</a>.

Microwave open-in-new

Microwave