X band
{{short description|Microwave radio frequency band from 8–12 GHz}}
{{about|the microwave spectrum|the Super NES and Sega Genesis online adapter|XBAND|the extension to the mediumwave broadcast band|AM expanded band|the radiation band that is not RF|X-ray|musical artists using the name X|X (disambiguation)}}
{{More citations needed|date=February 2008}}
{{MWband
| name = IEEE X band
| freq = 8.0–12.0 GHz
| wave = 3.75–2.5 cm
| bands = {{startplainlist|class=nowrap}}
{{endplainlist}}
}}
The X band is the designation for a band of frequencies in the microwave radio region of the electromagnetic spectrum. In some cases, such as in communication engineering, the frequency range of the X band is set at approximately 7.0–11.2 GHz.{{citation needed|date=August 2017}} In radar engineering, the frequency range is specified by the Institute of Electrical and Electronics Engineers (IEEE) as 8.0–12.0 GHz. The X band is used for radar, satellite communication, and wireless computer networks.
Radar
{{see also|Sea-based X-band Radar|AN/TPY-2|AN/SPY-3|AN/MPQ-64 Sentinel}}
File:Radar antennas on USS Theodore Roosevelt SPS-64.jpg antenna on a ship]]
X band is used in radar applications, including continuous-wave, pulsed, single-polarization, dual-polarization, synthetic aperture radar, and phased arrays. X-band radar frequency sub-bands are used in civil, military, and government institutions for weather monitoring, air traffic control, maritime vessel traffic control, defense tracking, and vehicle speed detection for law enforcement.{{Cite web |url=http://www.everythingweather.com/weather-radar/bands.shtml |title=Radar Bands |website=www.everythingweather.com}}{{cite web |title=What are S- and X-Band Radar and How Are They Used Today? |url=https://www.leonardodrs.com/news/thought-leadership/what-are-s-and-x-band-radar-and-how-are-they-used-today/ |website=Leonardo.com |publisher=Leonardo DRS |access-date=3 July 2024 |date=December 19, 2022}}
X band is often used in modern radars. The shorter wavelengths of the X band provide higher-resolution imagery from high-resolution imaging radars for target identification and discrimination. X-band weather radars offer significant potential for short-range observations, but the loss of signal strength (attenuation) under rainy conditions limits their use at longer range.Matrosov, S. Y., Kennedy, P. C. and Cifelli, R., 2014. Experimentally based estimates of relations between X-band radar signal attenuation characteristics and differential phase in rain. Journal of Atmospheric and Oceanic Technology, 31(11), pp. 2442–2450.
= Terrestrial communications and networking =
The X band 10.15 to 10.7 GHz segment is used for terrestrial broadband in many countries, such as Brazil, Mexico, Saudi Arabia, Denmark, Ukraine, Spain and Ireland.{{cite web |title=Broadband Wireless |url=http://ogierelectronics.com/broadband-wireless.php |access-date=5 May 2020}} Alvarion, CBNL, CableFree and Ogier make systems for this, though each has a proprietary airlink. DOCSIS (Data Over Cable Service Interface Specification) the standard used for providing cable internet to customers, uses some X band frequencies. The home / business customer-premises equipment (CPE) has a single coaxial cable with a power adapter connecting to an ordinary cable modem. The local oscillator is usually 9750 MHz, the same as for Ku band satellite TV LNB. Two way applications such as broadband typically use a 350 MHz TX offset.
= Space communications =
{{Further|X Band Satellite Communication}}
= Space communications for science and research =
File:Canberra Deep Dish Communications Complex - GPN-2000-000502.jpg 70 meter X-band spacecraft communication antenna at the Canberra Deep Space Communication Complex, Australia.]]
Small portions of the X band are assigned by the International Telecommunication Union (ITU) exclusively for deep space telecommunications. The primary user of this allocation is the American NASA Deep Space Network (DSN). DSN facilities are in Goldstone, California (in the Mojave Desert), near Canberra, Australia, and near Madrid, Spain, and provide continual communications from the Earth to almost any point in the Solar System independent of Earth rotation. (DSN stations are also capable of using the older and lower S band deep-space radio communications allocations, and some higher frequencies on a more-or-less experimental basis, such as in the K band.)
Notable deep space probe programs that have employed X band communications include the Viking Mars landers; the Voyager missions to Jupiter, Saturn, and beyond; the Galileo Jupiter orbiter; the New Horizons mission to Pluto and the Kuiper belt, the Curiosity rover and the Cassini-Huygens Saturn orbiter.{{cite web |title=Radio Science Subsystem (RSS) |url=https://solarsystem.nasa.gov/missions/cassini/mission/spacecraft/cassini-orbiter/radio-science-subsystem/ |website=NASA Science Solar System Exploration |access-date=23 August 2022}}
An important use of the X band communications came with the two Viking program landers. When the planet Mars was passing near or behind the Sun, as seen from the Earth, a Viking lander would transmit two simultaneous continuous-wave carriers, one in the S band and one in the X band in the direction of the Earth, where they were picked up by DSN ground stations. By making simultaneous measurements at the two different frequencies, the resulting data enabled theoretical physicists to verify the mathematical predictions of Albert Einstein's General Theory of Relativity. These results are some of the best confirmations of the General Theory of Relativity.{{cn|date=December 2023}}
The new European double Mars Mission ExoMars will also use X band communication, on the instrument LaRa, to study the internal structure of Mars, and to make precise measurements of the rotation and orientation of Mars by monitoring two-way Doppler frequency shifts between the surface platform and Earth. It will also detect variations in angular momentum due to the redistribution of masses, such as the migration of ice from the polar caps to the atmosphere.{{cn|date=December 2023}}
=X band NATO frequency requirements=
The International Telecommunication Union (ITU), the international body which allocates radio frequencies for civilian use, is not authorised to allocate frequency bands for military radio communication. This is also the case pertaining to X band military communications satellites. However, in order to meet military radio spectrum requirements, e.g. for fixed-satellite service and mobile-satellite service, the NATO nations negotiated the NATO Joint Civil/Military Frequency Agreement (NJFA).{{Cite web|url=http://www.akos-rs.si/files/Zakonodaja/Direktive_in_priporocila/mednarodni_sporazumi/CM-Ag.pdf|title=NATO Joint Civil/Military Frequency Agreement (NJFA)|access-date=2016-01-08|archive-date=2016-03-04|archive-url=https://web.archive.org/web/20160304102758/http://www.akos-rs.si/files/Zakonodaja/Direktive_in_priporocila/mednarodni_sporazumi/CM-Ag.pdf|url-status=dead}}
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! (a) | (b) | (c) | (d) |
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| colspan="4" bgcolor="DCDCDC"| | |||
| 7250
|7250-7750 | FIXED |1. Essential military requirements for satellite downlinks; the mobile satellite sub-band 7250-7300 MHz is for naval and land mobile earth stations. |1. This is a harmonised NATO band type 1for satellite downlinks. 2. 7250-7300 MHz is paired with 7975-8025 MHz for the MOBILE-SATELLlTE allocation. from the other services. | |||
| 7750
|7750-7900 | FIXED | Military requirements for existing NATO fixed systems in some countries. | |
| 7900-8400 MHz | FIXED-SATELLlTE (E-s), |1. Essential military requirements for satellite uplinks; the mobile satellite sub-band 7975-8025 MHz is for naval and land mobile satellite earth stations. |1. This is a harmonised NATO band type 1 for satellite uplinks. | |||
| 8500 MHz- 10.5 GHz | RADIOLOCATION Radiolocation | Military requirement for land, airborne and naval radars. | Harmonised NATO band type 2 in selected sub-bands is desirable. |
Amateur radio
The Radio Regulations of the International Telecommunication Union allow amateur radio operations in the frequency range 10.000 to 10.500 GHz,{{Cite web|url=http://www.iaru-r1.org/VHF_Handbook_V5_11.pdf|archive-url=https://web.archive.org/web/20090205161745/http://www.iaru-r1.org/VHF_Handbook_V5_11.pdf |url-status=dead |title=VHF Handbook of IARU Region 1 (2006), pg. 50|archive-date=February 5, 2009}} and amateur satellite operations are allowed in the range 10.450 to 10.500 GHz. This is known as the 3-centimeter band by amateurs and the X-band by AMSAT.
Other uses
Motion detectors often use 10.525 GHz.{{Cite web|url=http://www.g3pho.free-online.co.uk/microwaves/wideband.htm|title=10GHz wideband transceiver|website=www.g3pho.free-online.co.uk}} 10.4 GHz is proposed for traffic light crossing detectors. Comreg in Ireland has allocated 10.450 GHz for traffic sensors as SRD.{{cite web|url=http://www.comreg.ie/radio_spectrum/exemptions.541.488.rslicensing.html |title=Radio Spectrum |access-date=June 1, 2011 |url-status=dead |archive-url=https://web.archive.org/web/20120318235802/http://www.comreg.ie/radio_spectrum/exemptions.541.488.rslicensing.html |archive-date=March 18, 2012 }}
Many electron paramagnetic resonance (EPR) spectrometers operate near 9.8 GHz.
Particle accelerators may be powered by X-band RF sources. The frequencies are then standardized at 11.9942 GHz (Europe) or 11.424 GHz (US),F. Peauger, A. Hamdi, S. Curt, S. Doebert, G. McMonagle, G. Rossat, K.M. Schirm, I. Syratchev, L. Timeo, S. Kuzikhov, A.A. Vikharev, A. Haase, D. Sprehn, A. Jensen, E.N. Jongewaard, C.D. Nantista and A. Vlieks: [http://accelconf.web.cern.ch/AccelConf/IPAC10/papers/THPEB053.pdf A 12 GHz RF POWER SOURC E FOR THE CLIC STUDY]{{cite web|url=https://www.jlab.org/conferences/FLS2012/talks/Thur/isu_jlab39_fls2012_57_final.PDF |title=Performance Comparison of S-band, C-band, and X-band RF Linac based XFELs| access-date=2023-09-10}} which is the second harmonic of C-band and fourth harmonic of S-band. The European X-band frequency is used for the Compact Linear Collider (CLIC).
Many Radio Astronomy facilities have receivers which work in the X-band including the Green Bank Telescope{{cite web | url=https://dss.gb.nrao.edu/receivers/summary|title=GBT Receiver Summary | website=greenbankobservatory.org|access-date=May 28, 2025 }} and the Very Large Array{{cite web|url=https://science.nrao.edu/facilities/vla/docs/manuals/oss2016A/performance/bands|title=VLA Frequency Bands and Tunability|website=science.nrao.edu | access-date=May 28, 2025}}. Radio Astronomy has a Frequency Allocation for (quiet) bands at 10.6-10.68 GHz, and 10.68-10.7 GHz, but the receivers work across a much wider range of the entire X-band (e.g. 7-12 GHz) trying to take advantages of as much bandwidth as possible to be sensitive to faint astronomical sources.
See also
References
{{Reflist}}
External links
- [https://www.ntia.doc.gov/osmhome/allochrt.pdf United States Frequency Allocations]
- [http://www.g3pho.free-online.co.uk/microwaves/wideband.htm 10GHz wideband transceiver]
{{radio spectrum}}
{{EMSpectrum}}