K band designates certain portions 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 either 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...

 domain or in the infrared

Infrared

Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...

 domain. The microwave K bands are used primarily for radar

Radar

Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...

 and satellite communications while the infrared K band is used for astronomical observations

Observational astronomy

Observational astronomy is a division of the astronomical science that is concerned with getting data, in contrast with theoretical astrophysics which is mainly concerned with finding out the measurable implications of physical models...

.

NATO K band

The NATO K band is defined as a frequency band between 20 and 40 GHz (0.75 - 1.5 cm wavelength).

IEEE K band

The IEEE K band is a portion of the radio spectrum

Radio spectrum

Radio spectrum refers to the part of the electromagnetic spectrum corresponding to radio frequencies – that is, frequencies lower than around 300 GHz ....

 in 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...

 range of frequencies ranging between 18 and 27 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....

. K band between 18 and 26.5 GHz is absorbed easily by water vapor

Water vapor

Water vapor or water vapour , also aqueous vapor, is the gas phase of water. It is one state of water within the hydrosphere. Water vapor can be produced from the evaporation or boiling of liquid water or from the sublimation of ice. Under typical atmospheric conditions, water vapor is continuously...

 (H₂O resonance peak at 22.24 GHz, 1.35 cm).

Subdivisions

The IEEE K band is conventionally divided into three sub-bands:

• K_a 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...
  
  : K-above band, 26.5–40 GHz, mainly used for radar and experimental communications.
• K-band 18-27 GHz
• K_u 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...
  
  : K-under band, 12–18 GHz, mainly used for satellite communications, terrestrial microwave communications, and radar, especially police traffic-speed detectors.

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...

 and amateur satellite operations in the frequency range 24.000 GHz to 24.250 GHz, which is known as the 1.2-centimeter band

1.2-centimeter band

The 1.2 centimeter or 24 GHz band is a portion of the SHF radio spectrum internationally allocated to amateur radio and amateur satellite use. The amateur radio band is between 24.00 GHz and 24.25 GHz, and the amateur satellite band is between 24.00 GHz and 24.05 GHz...

. It is also referred to as the K 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...

.

Infrared astronomy

In infrared astronomy

Infrared astronomy

Infrared astronomy is the branch of astronomy and astrophysics that studies astronomical objects visible in infrared radiation. The wavelength of infrared light ranges from 0.75 to 300 micrometers...

, the K band refers to a different frequency range atmospheric transmission window centered on 2.2 microns (in the near-infrared 136 THz range).

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 X band The X band is a segment of the microwave radio region of the electromagnetic spectrum. 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 . In radar engineering, the frequency range is specified...	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	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, seehttp://www.radioing.com/eengineer/bands.html and http://www.microwaves101.com/encyclopedia/letterbands.cfm. For other definitions see Letter Designations of Microwave Bands