Frequency range | 27–40GHz |
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Wavelength range | 11.1–7.5mm |
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TheKa band (pronounced as either "kay-ay band" or "ka band") is a portion of themicrowave part of theelectromagnetic spectrum. The designation "Ka band" is from Kurz-above, which stems from the German wordkurz, meaning "short".[1]
There is no standard definition of the Ka band.IEEE Standard letter designations for Radar Bands define the nominal frequency range for the Ka band in the range 27–40 gigahertz (GHz) in Tables 1 and 2 of IEEE Standard 521[2]i.e. wavelengths from slightly over one centimeter down to 7.5 millimeters.[3]TheITU however approves Ka band satellite networks in the 17.3-31 GHz frequency range,[4]with most Ka band satellite networks having uplinks in the 27.5–31 GHz and downlinks in the 17.7–21.2 GHz range.[4]
The band is called Ka, short for "K-above" because it is the upper part of the original (now obsolete)NATO K band, which was split into three bands because of the presence of the atmosphericwater vapour resonance peak at 22.24 GHz (1.35 cm), which made the centre unusable for long range transmission. The 30/20 GHz band is used incommunications satelliteuplinks in either the 27.5 GHz or 31 GHz bands,[5] and in high-resolution, close-rangetargeting radars aboard military aeroplanes. Some frequencies in this radio band are used for vehicle speed detection by law enforcement.[6] TheKepler Mission used this frequency range to downlink the scientific data collected by the space telescope.[7] This frequency is also used forremote sensing of clouds by radar, by both ground-based[8] or satellite[9] systems such asINCUS.
In satellite communications, the Ka band allows higher bandwidth communication.[10] It was first used in the experimentalACTS Gigabit Satellite Network, and is currently used for high-throughputsatellite Internet access ingeostationary orbit (GEO) by theInmarsat I-5 system,[11]Kacific K-1 satellite,[12] the ViaSat 1, 2, and 3 satellites[13] among others; inlow Earth orbit (LEO) by theSpaceXStarlink system[14] and theIridium Next satellite series;[15] it is also used inmedium Earth orbit (MEO) by theSESO3b system;[16] and theJames Webb Space Telescope.[17]
Planned future satellite projects using the Ka band includeAmazon Leo (formerly "Project Kuiper")satellite internet constellation in LEO,[18]SES's multi-orbit satellite internet system of theSES-17 satellite in GEO (launched in October 2021; in position and fully operational in June 2022)[19] and theO3b mPOWER constellation in MEO (first two, of 13 satellites, launched December 2022 and service started in April 2024).[20][21][22]
The Ka band is more susceptible torain attenuation than is theKu band, which in turn is more susceptible than theC band.[23][24] The frequency is commonly used bycosmic microwave background experiments.5th generation mobile networks will also partially overlap with the Ka band (28, 38, and 60 GHz).[citation needed]
{{cite journal}}:Cite journal requires|journal= (help)Radio spectrum (ITU) | |||||||||||||
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