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X band

X band

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The X band is a segment of the microwave
Microwave
Microwaves, a subset of radio waves, have wavelengths ranging from as long as one meter to as short as one millimeter, or equivalently, with frequencies between 300 MHz and 300 GHz. This broad definition includes both UHF and EHF , and various sources use different boundaries...

 radio
Radio
Radio is the transmission of signals through free space by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space...

 region of the electromagnetic spectrum
Electromagnetic spectrum
The electromagnetic spectrum is the range of all possible frequencies of electromagnetic radiation. The "electromagnetic spectrum" of an object is the characteristic distribution of electromagnetic radiation emitted or absorbed by that particular object....

. In some cases, such as in communication engineering, the frequency range of X band is rather indefinitely set at approximately 7.0 to 11.2 gigahertz (GHz
GHZ
GHZ or GHz may refer to:# Gigahertz .# Greenberger-Horne-Zeilinger state — a quantum entanglement of three particles.# Galactic Habitable Zone — the region of a galaxy that is favorable to the formation of life....

). In radar engineering, the frequency range is specified by the IEEE at 8.0 to 12.0 GHz.

The term "X-band" is also used informally and inaccurately to refer to the extended AM broadcast band
Extended AM broadcast band
The extended mediumwave broadcast band, commonly known as the [AM] expanded band, is a broadcast frequency allocation which moved the upper limit of the AM bandplan from 1610 to 1700 kHz.- History :...

, where the "X" stands for "extended".

Satellite communications


For military communications satellite
Communications satellite
A communications satellite is an artificial satellite stationed in space for the purpose of telecommunications...

s, the International Telecommunications Union (ITU) has assigned the X band uplink frequency band (for sending modulated signals) as from 7.9 to 8.4 GHz. The ITU-assigned downlink frequency band (for receiving signals) is from 7.25 to 7.75 GHz. The US military uses all frequencies in this spectrum; however, they use select signals on the frequencies throughout this spectrum. The typical local oscillator
Local oscillator
A local oscillator is an electronic device used to generate a signal normally for the purpose of converting a signal of interest to a different frequency using a mixer. This process of frequency conversion, also referred to as heterodyning, produces the sum and difference frequencies of the...

 frequency of an X band low-noise block converter
Low-noise block converter
A low-noise block downconverter is the receiving device of a parabolic satellite dish antenna of the type commonly used for satellite TV reception...

 (LNB) is 6300 MHz. Both of these frequency bands are 500 MHz wide.

In engineering, this pair of frequency bands may be referred to as the 8 / 7 GHz X band satellite communications system.

Radar


X band is used in radar applications including continuous-wave
Continuous wave
A continuous wave or continuous waveform is an electromagnetic wave of constant amplitude and frequency; and in mathematical analysis, of infinite duration. Continuous wave is also the name given to an early method of radio transmission, in which a carrier wave is switched on and off...

, pulsed, single-polarization, dual-polarization, synthetic aperture radar
Synthetic aperture radar
Synthetic-aperture radar is a form of radar whose defining characteristic is its use of relative motion between an antenna and its target region to provide distinctive long-term coherent-signal variations that are exploited to obtain finer spatial resolution than is possible with conventional...

, and phased array
Phased array
In wave theory, a phased array is an array of antennas in which the relative phases of the respective signals feeding the antennas are varied in such a way that the effective radiation pattern of the array is reinforced in a desired direction and suppressed in undesired directions.An antenna array...

s. X band radar frequency sub-bands are used in civil
Civilian
A civilian under international humanitarian law is a person who is not a member of his or her country's armed forces or other militia. Civilians are distinct from combatants. They are afforded a degree of legal protection from the effects of war and military occupation...

, military, and government
Government
Government refers to the legislators, administrators, and arbitrators in the administrative bureaucracy who control a state at a given time, and to the system of government by which they are organized...

 institutions for weather monitoring
Weather radar
Weather radar, also called weather surveillance radar and Doppler weather radar, is a type of radar used to locate precipitation, calculate its motion, estimate its type . Modern weather radars are mostly pulse-Doppler radars, capable of detecting the motion of rain droplets in addition to the...

, air traffic control
Air traffic control
Air traffic control is a service provided by ground-based controllers who direct aircraft on the ground and in the air. The primary purpose of ATC systems worldwide is to separate aircraft to prevent collisions, to organize and expedite the flow of traffic, and to provide information and other...

, maritime vessel traffic control
Vessel Traffic Service
A vessel traffic service is a marine traffic monitoring system established by harbour or port authorities, similar to air traffic control for aircraft...

, defense
Defense (military)
Defense has several uses in the sphere of military application.Personal defense implies measures taken by individual soldiers in protecting themselves whether by use of protective materials such as armor, or field construction of trenches or a bunker, or by using weapons that prevent the enemy...

 tracking, and vehicle speed detection
Radar gun
A radar speed gun is a small doppler radar unit used to measure the speed of moving objects, including vehicles, pitched baseballs, runners and other moving objects. Radar speed guns may be hand-held, vehicle-mounted or static...

 for law enforcement.Radar Bands

X band is often used in modern radars. The shorter wavelength
Wavelength
In physics, the wavelength of a sinusoidal wave is the spatial period of the wave—the distance over which the wave's shape repeats.It is usually determined by considering the distance between consecutive corresponding points of the same phase, such as crests, troughs, or zero crossings, and is a...

s of the X band allow for higher resolution imagery from high-resolution imaging radar
Imaging radar
Traditional radar sends directional pulses of electromagnetic energy and detects the presence, position and motion of an object by analyzing the portion of the energy reflected from the object back to the radar station. Imaging radar attempts to form a picture of the object as well, by mapping...

s for target identification and discrimination.

Terrestrial communications and networking


In Ireland, Libya, Saudi Arabia and Canada, the X band 10.15 to 10.7 segment is used for terrestrial broadband. Alvarion
Alvarion
Alvarion Ltd. , is a 4G communications company. The company manufactures and exports a range of network solutions, including WiMAX, IEEE, PtMP, TD-LTE and WiFi to service providers and enterprises covering a variety of industries such as mobile broadband, residential and business broadband,...

, Cambridge, and Ogier make systems for this, though these are all incompatible. The Ogier system is a full duplex Transverter
Transverter
A transverter is a radio frequency device that consists of an upconverter and a downconverter in one unit. Transverters are used in conjunction with transceivers to change the range of frequencies over which the transceiver can communicate....

 used for DOCSIS
DOCSIS
Data Over Cable Service Interface Specification is an international telecommunications standard that permits the addition of high-speed data transfer to an existing cable TV system...

 over microwave. The home / Business CPE
CPE
-Biochemistry:* Carboxypeptidase E* Clostridium perfringens enterotoxin* Cytopathic effect* Cytoplasmic polyadenylation element-Telecommunications:...

 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


Portions of the X band are assigned by the International Telecommunications Union (ITU) exclusively for deep space telecommunications. The primary user of this allocation is the American NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

 Deep Space Network
Deep Space Network
The Deep Space Network, or DSN, is a world-wide network of large antennas and communication facilities that supports interplanetary spacecraft missions. It also performs radio and radar astronomy observations for the exploration of the solar system and the universe, and supports selected...

 (DSN). DSN facilities are located in Goldstone, California (in the Mojave Desert
Mojave Desert
The Mojave Desert occupies a significant portion of southeastern California and smaller parts of central California, southern Nevada, southwestern Utah and northwestern Arizona, in the United States...

), near Canberra, Australia, and near Madrid, Spain.

These three stations, located approximately 120 degrees apart in longitude
Longitude
Longitude is a geographic coordinate that specifies the east-west position of a point on the Earth's surface. It is an angular measurement, usually expressed in degrees, minutes and seconds, and denoted by the Greek letter lambda ....

, provide continual communications from the Earth to almost any point in the Solar System
Solar System
The Solar System consists of the Sun and the astronomical objects gravitationally bound in orbit around it, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago. The vast majority of the system's mass is in the Sun...

 independent of Earth rotation. DSN stations are capable of using the older and lower S band
S band
The S band is defined by an IEEE standard for radio waves with frequencies that range from 2 to 4 GHz, crossing the conventional boundary between UHF and SHF at 3.0 GHz. It is part of the microwave band of the electromagnetic spectrum...

 deep-space radio communications allocations, and some higher frequencies on a more-or-less experimental basis, such as in the K band
K band
K band designates certain portions of the electromagnetic spectrum, in either the microwave domain or in the infrared domain. The microwave K bands are used primarily for radar and satellite communications while the infrared K band is used for astronomical observations.-NATO K band:The NATO K band...

.

Notable deep space probe
Space probe
A robotic spacecraft is a spacecraft with no humans on board, that is usually under telerobotic control. A robotic spacecraft designed to make scientific research measurements is often called a space probe. Many space missions are more suited to telerobotic rather than crewed operation, due to...

 programs that have employed X band communications include the Viking
Viking
The term Viking is customarily used to refer to the Norse explorers, warriors, merchants, and pirates who raided, traded, explored and settled in wide areas of Europe, Asia and the North Atlantic islands from the late 8th to the mid-11th century.These Norsemen used their famed longships to...

 Mars
Mars
Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...

 landers; the Voyager
Voyager program
The Voyager program is a U.S program that launched two unmanned space missions, scientific probes Voyager 1 and Voyager 2. They were launched in 1977 to take advantage of a favorable planetary alignment of the late 1970s...

 missions to Jupiter
Jupiter
Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...

, Saturn
Saturn
Saturn is the sixth planet from the Sun and the second largest planet in the Solar System, after Jupiter. Saturn is named after the Roman god Saturn, equated to the Greek Cronus , the Babylonian Ninurta and the Hindu Shani. Saturn's astronomical symbol represents the Roman god's sickle.Saturn,...

, and beyond; the Galileo Jupiter orbiter; the New Horizons
New Horizons
New Horizons is a NASA robotic spacecraft mission currently en route to the dwarf planet Pluto. It is expected to be the first spacecraft to fly by and study Pluto and its moons, Charon, Nix, Hydra and S/2011 P 1. Its estimated arrival date at the Pluto-Charon system is July 14th, 2015...

 mission to Pluto
Pluto
Pluto, formal designation 134340 Pluto, is the second-most-massive known dwarf planet in the Solar System and the tenth-most-massive body observed directly orbiting the Sun...

 and the Kuiper belt
Kuiper belt
The Kuiper belt , sometimes called the Edgeworth–Kuiper belt, is a region of the Solar System beyond the planets extending from the orbit of Neptune to approximately 50 AU from the Sun. It is similar to the asteroid belt, although it is far larger—20 times as wide and 20 to 200 times as massive...

, and the Cassini-Huygens
Cassini-Huygens
Cassini–Huygens is a joint NASA/ESA/ASI spacecraft mission studying the planet Saturn and its many natural satellites since 2004. Launched in 1997 after nearly two decades of gestation, it includes a Saturn orbiter and an atmospheric probe/lander for the moon Titan, although it has also returned...

 Saturn orbiter.

An important use of the X band communications came with the two Viking program
Viking program
The Viking program consisted of a pair of American space probes sent to Mars, Viking 1 and Viking 2. Each spacecraft was composed of two main parts, an orbiter designed to photograph the surface of Mars from orbit, and a lander designed to study the planet from the surface...

 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
Albert Einstein
Albert Einstein was a German-born theoretical physicist who developed the theory of general relativity, effecting a revolution in physics. For this achievement, Einstein is often regarded as the father of modern physics and one of the most prolific intellects in human history...

's General Theory of Relativity. These results are some of the best confirmations of the General Theory of Relativity.

Amateur radio


The Radio Regulations of the International Telecommunication Union
International Telecommunication Union
The International Telecommunication Union is the specialized agency of the United Nations which is responsible for information and communication technologies...

 allow amateur radio
Amateur radio
Amateur radio is the use of designated radio frequency spectrum for purposes of private recreation, non-commercial exchange of messages, wireless experimentation, self-training, and emergency communication...

 operations in the frequency range 10.000 to 10.500 GHz,VHF Handbook of IARU Region 1 (2006), pg. 50 and amateur satellite operations are allowed in the range 10.450 to 10.500 GHz. This is known as the 3-centimeter band
3-centimeter band
The 3 centimeter or 10 GHz band is a portion of the SHF radio spectrum internationally allocated to amateur radio and amateur satellite use on a secondary basis. The amateur radio band is between 10.00 GHz and 10.50 GHz, and the amateur satellite band is between 10.45 GHz and 10.50 GHz...

 by amateurs and the X-band by AMSAT
AMSAT
AMSAT is a name for amateur radio satellite organizations worldwide, but in particular the Radio Amateur Satellite Corporation with headquarters at Silver Spring, Maryland, near Washington DC. AMSAT organizations design, build, arrange launches for, and then operate satellites carrying amateur...

.

Motion detection


Motion detector
Motion detector
A motion detector is a device for motion detection. That is, it is a device that contains a physical mechanism or electronic sensor that quantifies motion that can be either integrated with or connected to other devices that alert the user of the presence of a moving object within the field of view...

s often use 10.525 GHz.10GHz Wideband Transceiver 10.4 GHz is proposed for traffic light
Traffic light
Traffic lights, which may also be known as stoplights, traffic lamps, traffic signals, signal lights, robots or semaphore, are signalling devices positioned at road intersections, pedestrian crossings and other locations to control competing flows of traffic...

 crossing detectors.
Comreg in Ireland has allocated 10.450GHz for Traffic Sensors as SRD .

Other microwave bands


The microwave spectrum is usually defined as electromagnetic energy ranging from approximately 1 GHz to 100 GHz in frequency, but older usage includes lower frequencies. Most common applications are within the 1 to 40 GHz range. Microwave frequency bands, as defined by the Radio Society of Great Britain
Radio Society of Great Britain
First founded in 1913 as the London Wireless Club, the Radio Society of Great Britain is the United Kingdom's recognised national society for amateur radio operators. The society's patron is Prince Philip, Duke of Edinburgh and it represents the interests of the UK’s 60,000 licensed radio amateurs...

 (RSGB), are shown in the table below:
L band
L band
L band refers to four different bands of the electromagnetic spectrum: 40 to 60 GHz , 1 to 2 GHz , 1565 nm to 1625 nm , and around 3.5 micrometres .-NATO L band:...

1 to 2 GHz
S band
S band
The S band is defined by an IEEE standard for radio waves with frequencies that range from 2 to 4 GHz, crossing the conventional boundary between UHF and SHF at 3.0 GHz. It is part of the microwave band of the electromagnetic spectrum...

2 to 4 GHz
C band
C band
The C band is a name given to certain portions of the electromagnetic spectrum, including wavelengths of microwaves that are used for long-distance radio telecommunications. The IEEE C-band - and its slight variations - contains frequency ranges that are used for many satellite communications...

4 to 8 GHz
X band 8 to 12 GHz
Ku band
Ku band
The Kμ band is a portion of the electromagnetic spectrum in the microwave range of frequencies. This symbol refers to —in other words, the band directly below the K-band...

12 to 18 GHz
K band
K band
K band designates certain portions of the electromagnetic spectrum, in either the microwave domain or in the infrared domain. The microwave K bands are used primarily for radar and satellite communications while the infrared K band is used for astronomical observations.-NATO K band:The NATO K band...

18 to 26.5 GHz
Ka band
Ka band
The Ka band covers the frequencies of 26.5–40 GHz. The Ka band is part of the K band of the microwave band of the electromagnetic spectrum. This symbol refers to "K-above" — in other words, the band directly above the K-band...

26.5 to 40 GHz
Q band
Q band
The Q band of the microwave part of the electromagnetic spectrum and ranges from 33 to 50 GHz. It sits above, and partly overlaps with, the U.S. IEEE designated Ka band . It sits below the U.S...

30 to 50 GHz
U band 40 to 60 GHz
V band
V band
The V band of the electromagnetic spectrum ranges from 50 to 75 GHz. The V band is not heavily used, except for millimeter wave radar research and other kinds of scientific research...

50 to 75 GHz
E band
E band
The NATO E band is the range of radio frequencies from 2 GHz to 3 GHz in the electromagnetic spectrum. This is equal to wave lengths between 15 cm and 10 cm. The E band is in the upper UHF range of the radio spectrum...

60 to 90 GHz
W band
W band
The W band of the microwave part of the electromagnetic spectrum ranges from 75 to 110 GHz. It sits above the U.S. IEEE designated V band in frequency, yet overlaps the NATO designated M band...

75 to 110 GHz
F band
F band
The F band is the range of radio frequencies from 90 GHz to 140 GHz in the electromagnetic spectrum. This is equal to wave lengths between 2.1 mm and 3.3 mm...

90 to 140 GHz
D band
D band
IEEE D band is the range of radio frequencies from 110 GHz to 170 GHz in the electromagnetic spectrum. This is equal to wave lengths between 1.8 mm and 2.7 mm...

110 to 170 GHz


Footnote: P band is sometimes incorrectly used for Ku Band. "P" for "previous" was a radar band used in the UK ranging from 250 to 500 MHz and now obsolete per IEEE Std 521.http://www.radioing.com/eengineer/bands.htmlhttp://www.microwaves101.com/encyclopedia/letterbands.cfm For other definitions see Letter Designations of Microwave Bands

See also

  • Cassegrain reflector
    Cassegrain reflector
    The Cassegrain reflector is a combination of a primary concave mirror and a secondary convex mirror, often used in optical telescopes and radio antennas....

  • Directional antenna
    Directional antenna
    A directional antenna or beam antenna is an antenna which radiates greater power in one or more directions allowing for increased performance on transmit and receive and reduced interference from unwanted sources....

  • XTAR
    XTAR
    XTAR LLC is a satellite communications company headquartered in Rockville, Maryland, with offices in Madrid, Spain and Palo Alto, California. It is a joint venture between Loral Space & Communications, which owns 56 percent, and HISDESAT, which owns 44 percent. The company is the first U.S...

  • Sea-based X band Radar
    Sea-based X-band Radar
    Sea-Based X-Band Radar is a floating, self-propelled, mobile radar station designed to operate in high winds and heavy seas. It is part of the U.S. Defense Department Ballistic Missile Defense System....

  • New Horizons#Telecommunications
  • Voyager program#Spacecraft design
  • Earth observation satellites transmission frequencies
    Earth observation satellites transmission frequencies
    The earth is constantly being monitored by a great number earth observation satellites. These artificial satellites have onboard sensors from which they gather data. The data is transmitted back to earth via radio frequency...

  • TerraSAR-X
    TerraSAR-X
    TerraSAR-X, a German Earth observation satellite, is a joint venture being carried out under a public-private-partnership between the German Aerospace Center DLR and EADS Astrium GmbH; the exclusive commercial exploitation rights are held by the geo-information service provider Infoterra GmbH....

    : a German Earth observation satellite

External links

  • http://www.ntia.doc.gov/osmhome/allochrt.pdf
  • http://www.g3pho.free-online.co.uk/microwaves/wideband.htm