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), i.e. wavelengths from slightly over one centimeter down to 7.5 millimeters. 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, 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. 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".
In satellite communications, the Ka band allows higher bandwidth communication. It was first used in the experimental ACTS Gigabit Satellite Network, and is currently used in the Inmarsat I-5 system and the SpaceX Starlink system and will be used in the Iridium Next satellite series,[clarification needed] Amazon's Project Kuiper satellite internet constellation, Kacific K-1 satellite,[when?] as well as the James Webb Space Telescope.
The Ka band is more susceptible to rain attenuation than is the Ku band, which in turn is more susceptible than the C band. 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).
- R. Ludwig, P. Bretchko, RF Circuit Design, Theory and Applications, Prentice Hall NJ, 2000.
- "Basics of Space Flight Section I. The Environment of Space".
- "Ka Band".
- Elert, Glenn. "Frequency of a Police Radar Gun".
- http://www.itwissen.info/definition/lexikon/K-Band-K-band.html (german)
- "Archived copy". Archived from the original on May 11, 2013. Retrieved August 6, 2013.CS1 maint: archived copy as title (link)
- "SpaceX seeks FCC permission for operating all first-gen Starlink in lower orbit". SpaceNews.com. 2020-04-21. Retrieved 2020-04-23.
- Foust, Jeff (15 December 2020). "Amazon unveils flat-panel customer terminal for Kuiper constellation". SpaceNews. Retrieved 29 December 2020.
- Miller, Peter. "Ka-Band – the future of satellite communication?" (pdf). Retrieved 2016-07-06.