The K_a band (pronounced as either "kay-ay band" or "ka band") is a portion of the

microwave Microwave is a form of electromagnetic radiation with wavelengths shorter than other radio waves but longer than infrared waves. Its wavelength ranges from about one meter to one millimeter, corresponding to frequency, frequencies between 300&n ...

part of the

electromagnetic spectrum The electromagnetic spectrum is the full range of electromagnetic radiation, organized by frequency or wavelength. The spectrum is divided into separate bands, with different names for the electromagnetic waves within each band. From low to high ...

. The designation "K_a-band" is from Kurz-above, which stems from the German word ''kurz,'' meaning "short". There is no standard definition of Ka-band.

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Standard letter designations for Radar Bands define the nominal frequency range for Ka band in the range 27–40

gigahertz The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), often described as being equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose formal expression in terms of SI base un ...

(GHz) in Tables 1 and 2 of IEEE Standard 521 i.e. wavelengths from slightly over one centimeter down to 7.5 millimeters. The ITU however approves Ka-band satellite networks in the 17.3-31 GHz frequency range, with most Ka-band satellite networks having uplinks in the 27.5–31 GHz and downlinks in the 17.7–21.2 GHz range. The band is called K_a, 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 atmospheric

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resonance peak at 22.24 GHz (1.35 cm), which made the center unusable for long range transmission. The 30/20 GHz band is used in

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uplinks in either the 27.5 GHz or 31 GHz bands, and in high-resolution, close-range targeting radars aboard military airplanes. Some frequencies in this radio band are used for vehicle speed detection by law enforcement. The Kepler Mission used this frequency range to downlink the scientific data collected by the space telescope. This frequency is also used for

remote sensing Remote sensing is the acquisition of information about an physical object, object or phenomenon without making physical contact with the object, in contrast to in situ or on-site observation. The term is applied especially to acquiring inform ...

of clouds by radar, by both ground-based or satellite systems such as

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. In satellite communications, the K_a band allows higher bandwidth communication. It was first used in the experimental ACTS Gigabit Satellite Network, and is currently used for high-throughput

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in geostationary orbit (GEO) by the

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I-5 system, Kacific K-1 satellite, the ViaSat 1, 2, and 3 satellites among others; in low Earth orbit (LEO) by the

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Starlink system and the Iridium Next satellite series; it is also used in medium Earth orbit (MEO) by the SES

O3b O3b is a satellite constellation in Medium Earth orbit (MEO) owned and operated by SES, and designed to provide lower-latency broadband connectivity to remote locations for mobile network operators and internet service providers, maritime, av ...

system; and the

James Webb Space Telescope The James Webb Space Telescope (JWST) is a space telescope designed to conduct infrared astronomy. As the largest telescope in space, it is equipped with high-resolution and high-sensitivity instruments, allowing it to view objects too old, Lis ...

. Planned future satellite projects using the K_a-band include

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's Project Kuiper satellite internet constellation in LEO, SES's multi-orbit satellite internet system of the SES-17 satellite in GEO (launched in October 2021; in position and fully operational in June 2022) and the

O3b mPOWER O3b mPOWER is a communications satellite system owned and operated by SES. The system uses high-throughput and low- latency satellites in a medium Earth orbit (MEO), along with ground infrastructure and intelligent software, to provide multip ...

constellation in MEO (first two, of 13 satellites, launched December 2022 and service started in April 2024). The K_a band is more susceptible to rain attenuation than is the , which in turn is more susceptible than the C band. The frequency is commonly used by

cosmic microwave background experiments This list is a compilation of experiments measuring the cosmic microwave background radiation, cosmic microwave background (CMB) radiation anisotropies and polarization since the first detection of the CMB by Arno Allan Penzias, Penzias and Rob ...

. 5th generation mobile networks will also partially overlap with the K_a band (28, 38, and 60 GHz).

References

{{DEFAULTSORT:Ka Band Microwave bands Satellite broadcasting

See also

References