Ka band

أرقام حزم الراديو حسب ITU

4 5 6 7 8 9 10 11 12

رموز حزم الراديو حسب ITU

VLF LF MF HF VHF UHF SHF EHF

NATO Radio bands

A B C D E F G H I J K L M

حـِزم الرادار حسب IEEE

HF VHF UHF L S C X Ku K Ka V W

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The Ka band (pronounced as either "kay-ay band" or "ka band") is a portion of the microwave part of the electromagnetic spectrum defined as frequencies in the range 26.5–40 gigahertz (GHz),[1] i.e. wavelengths from slightly over one centimeter down to 7.5 millimeters.[2] The band is called Ka, short for "K-above" because it is the upper part of the original NATO K band, which was split into three bands because of the presence of the atmospheric water vapor 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 communications satellite uplinks in either the 27.5 GHz and 31 GHz bands,[3] and high-resolution, close-range targeting radars aboard military airplanes. Some frequencies in this radio band are used for vehicle speed detection by law enforcement.[4] The Kepler Mission used this frequency range to downlink the scientific data collected by the space telescope.

The designation "Ka-band" is from Kurz-above, which stems from the German word kurz meaning "short".[5]

In satellite communications, the Ka band allows higher bandwidth communication.[6] It was first used in the experimental ACTS Gigabit Satellite Network, and is currently used for high-throughput satellite Internet access in geostationary orbit (GEO) by the Inmarsat I-5 system[7] and Kacific K-1 satellite;[8] in low Earth orbit (LEO) by the SpaceX Starlink system[9] and the Iridium Next satellite series;[10] it is also use in medium Earth orbit (MEO) by the SES O3b system;[11] and the James Webb Space Telescope.[12]

Planned future satellite projects using Ka-band include Amazon's Project Kuiper satellite internet constellation in LEO,[13] 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[14]) and O3b mPOWER constellation in MEO (to be launched 2022–2024, and starting service in Q3 2023).[15][16][17]

The Ka band is more susceptible to rain attenuation than is the Ku band, which in turn is more susceptible than the C band.[18] The frequency is commonly used by cosmic microwave background experiments. The 5th generation mobile networks will also partially overlap with Ka band (28, 38, and 60 GHz).[بحاجة لمصدر]

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المراجع

  1. ^ R. Ludwig, P. Bretchko, RF Circuit Design, Theory and Applications, Prentice Hall NJ, 2000.
  2. ^ "Basics of Space Flight Section I. The Environment of Space".
  3. ^ "Ka Band". 6 April 2019.
  4. ^ Elert, Glenn. "Frequency of a Police Radar Gun".
  5. ^ http://www.itwissen.info/definition/lexikon/K-Band-K-band.html (german)
  6. ^ L/Ku/Ka-band satellites – what does it all mean? Get Connected. 11 September 2017. Accessed 27 April 2021
  7. ^ "Inmarsat - Inmarsat Announces $1.2bn Investment in Next Generation Ka-Band Satellite Network - Press Release". Archived from the original on May 11, 2013. Retrieved August 6, 2013.
  8. ^ Kacific Reveals Plans for Second Satellite Via Satellite. 30 October 2020. Accessed 28 April 2021
  9. ^ "SpaceX seeks FCC permission for operating all first-gen Starlink in lower orbit". SpaceNews.com (in الإنجليزية الأمريكية). 2020-04-21. Retrieved 2020-04-23.
  10. ^ Iridium-NEXT Gunter's Space Page. Accessed 28 April 2021
  11. ^ Four New Satellites Ride Into Space To Join Growing SES Constellation Space.com 4 April 2019. Accessed 28 April 2021
  12. ^ James Webb Space Telescope User Documentation - JWST Communications Subsystem Space Terlescope Science Institute. Accessed 28 April 2021
  13. ^ Foust, Jeff (15 December 2020). "Amazon unveils flat-panel customer terminal for Kuiper constellation". SpaceNews. Retrieved 29 December 2020.
  14. ^ SES-17 Ka-Band Satellite is Now Operational Via Satellite. 16 June 2022. Accessed 27 June 2022
  15. ^ SES’ Satellites’ Agility Achieved With ARC and Kythera Space Solutions SatNews. 24 November 2020. Accessed 28 April 2021
  16. ^ "SES YTD 2021 Results" (PDF). SES S.A. 4 November 2021. p. 4. Retrieved 27 January 2022.
  17. ^ SES eagerly awaiting the flexibility O3b mPower promises Space News. 11 November 2022. Accessed 3 December 2022
  18. ^ Miller, Peter. "Ka-Band – the future of satellite communication?" (PDF). Retrieved 2016-07-06.


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