Ku band

Short description: Range of radio frequencies from 11-20 GHz

IEEE Ku band

Frequency range

| 12–18 GHz

|

Wavelength range

| 2.5–1.67 cm

Related bands

* J (NATO)
* SHF (ITU)

Radio bands

ITU
|  1 (ELF)|  2 (SLF)|  3 (ULF)|  4 (VLF)

|
|
|

5 (LF)|  6 (MF)|  7 (HF)|  8 (VHF)
9 (UHF)|  10 (SHF)|  11 (EHF)|  12 (THF)
EU / NATO / US ECM

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

IEEE

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

Other TV and radio

* I
* II
* III
* IV
* V
* VI

* v
* t
* e

The Ku band (/ˌkeɪˈjuː/) is the portion of the electromagnetic spectrum in the microwave range of frequencies from 12 to 18 gigahertz (GHz). The symbol is short for "K-under" (originally German: Kurz-unten), because it is the lower part of the original NATO K band, which was split into three bands (Ku, K, and Ka) 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. In radar applications, it ranges from 12 to 18 GHz according to the formal definition of radar frequency band nomenclature in IEEE Standard 521–2002.[1][2]

Ku band is primarily used for satellite communications, most notably the downlink used by direct broadcast satellites to broadcast satellite television, and for specific applications such as NASA's Tracking Data Relay Satellite used for International Space Station (ISS) communications and SpaceX Starlink satellites.[3] Ku band satellites are also used for backhauls and particularly for satellite from remote locations back to a television network's studio for editing and broadcasting. The band is split by the International Telecommunication Union (ITU) into multiple segments that vary by geographical region. NBC was the first television network to uplink a majority of its affiliate feeds via Ku band in 1983.

Some frequencies in this radio band are employed in radar guns used by law enforcement to detect vehicles speeding, especially in Europe.[4]

## Contents

* 1 Segments and regions
* 1.1 America
* 1.2 Europe and Africa
* 1.3 Australia
* 1.4 Indonesia
* 1.5 Others
* 2 Advantages
* 3 Disadvantages
* 4 See also
* 5 References
* 6 External links

## Segments and regions

One use of the band is direct-broadcast satellite television. A satellite dish on a residence, which receives satellite television channels over a Ku band microwave beam from a broadcast communications satellite in a geostationary orbit 35,700 kilometres (22,000 miles) above the Earth.

### America

Segments in most of North and South America are represented by ITU Region 2 from 11.7 to 12.2 GHz (Local Oscillator Frequency (LOF) 10.75 to 11.25 GHz), allocated to the FSS (fixed satellite service), uplink from 14.0 to 14.5 GHz. There are more than 22 FSS Ku band satellites orbiting over North America, each carrying 12 to 48 transponders, 20 to 120 watts per transponder, and requiring a 0.8-m to 1.5-m antenna for clear reception.

The 12.2 to 12.7 GHz (LOF 11.25 to 11.75 GHz) segment is allocated to the BSS (broadcasting satellite service). BSS (DBS direct broadcast satellites) normally carry 16 to 32 transponders of 27 MHz bandwidth running at 100 to 240 watts of power, allowing the use of receiver antennas as small as 18 inches (450 mm).

### Europe and Africa

Segments in those regions are represented by ITU Region 1, and they are the 11.45 to 11.7 and 12.5 to 12.75 GHz bands are allocated to the FSS (fixed satellite service, uplink 14.0 to 14.5 GHz). In Europe Ku band is used from 10.7 to 12.75 GHz (LOF Low 9.75 GHz, LOF High 10.6 GHz) for direct broadcast satellite services such as those carried by the Astra satellites. The 11.7 to 12.5 GHz segment is allocated to the BSS (broadcasting satellite service).

### Australia

Australia is part of ITU Region 3 and the Australian regulatory environment provides a class license that covers downlinking from 11.70 GHz to 12.75 GHz and uplinking from 14.0 GHz to 14.5 GHz.[5]

### Indonesia

The ITU has categorized Indonesia as Region P, countries with very high rain precipitation. This statement has made many people unsure about using Ku-band (11 – 18 GHz) in Indonesia. Using frequencies higher than 10 GHz in a heavy rain area usually gives poor results. This problem can be solved by using an appropriate link budget when designing the wireless communication link. Higher power can overcome the loss to rain fade.

Measurements of rain attenuation in Indonesia have been done for satellite communication links in Padang, Cibinong, Surabaya and Bandung. The DAH Model for rain attenuation prediction is valid for Indonesia, as is the ITU model. The DAH model has become an ITU recommendation since 2001 (Recommendation No. ITU-R P.618-7). This model can create a 99.7% available link so that Ku-band can be applied in Indonesia.

Use of the Ku-band for satellite communications in tropical regions like Indonesia is becoming more frequent. Several satellites above Indonesia have Ku-band transponders, and even Ka band transponders. NSS 6, launched in December 2002 and positioned at 95° East, contains only Ku-band transponders with a footprint on Indonesia (Sumatra, Java, Borneo, Celebes, Bali, Nusa Tenggara, Moluccas). NSS 6 is intended to be replaced by SES-12 at the same location, which launched in June 2018 and carries 54 Ku-band transponders. The IPSTAR 1 satellite, launched in 2004 also uses Ku band footprints. Other satellites that provides Ku band covers Indonesia are MEASAT-3b, JCSAT-4B, AsiaSat 5, ST-2, Chinasat 11, Koreasat 8/ABS-2, SES-8, SES-9, Telkom-3S, and Nusantara Satu.

### Others

Other ITU allocations have been made within the Ku band to the fixed service (microwave towers), radio astronomy service, space research service, mobile service, mobile satellite service, radiolocation service (radar), amateur radio service, and radionavigation. However, not all of these services are actually operating in this band and others are only minor users.

## Advantages

Compared with C-band, Ku band is not similarly restricted in power to avoid interference with terrestrial microwave systems, and the power of its uplinks and downlinks can be increased. This higher power also translates into smaller receiving dishes and points out a generalization between a satellite's transmission and a dish's size. As the power increases, the size of an antenna's dish will decrease.[6] This is because the purpose of the dish element of the antenna is to collect the incident waves over an area and focus them all onto the antenna's actual receiving element, mounted in front of the dish (and pointed back towards its face); if the waves are more intense, fewer of them need to be collected to achieve the same intensity at the receiving element.

A major attraction of the band over lower frequency microwave bands is that the shorter wavelengths allow sufficient angular resolution to separate the signals of different communication satellites to be achieved with smaller terrestrial parabolic antennas. From the Rayleigh criterion, the diameter of a parabolic dish required to create a radiation pattern with a given angular beamwidth (gain) is proportional to the wavelength, and thus inversely proportional to the frequency. At 12 GHz a 1-meter dish is capable of focusing on one satellite while sufficiently rejecting the signal from another satellite only 2 degrees away. This is important because satellites in FSS (Fixed Satellite Service) service (11.7-12.2 GHz in the U.S.) are only 2 degrees apart. At 4 GHz (C-band) a 3-meter dish is required to achieve this narrow angular resolution. Note the inverse linear correlation between dish size and frequency. For Ku satellites in DBS (Direct Broadcast Satellite) service (12.2-12.7 GHz in the U.S.) dishes much smaller than 1-meter can be used because those satellites are spaced 9 degrees apart. As power levels on both C and Ku band satellites have increased over the years, dish beam-width has become much more critical than gain.

The Ku band also offers a user more flexibility. A smaller dish size and a Ku band system's freedom from terrestrial operations simplifies finding a suitable dish site. For the end users Ku band is generally cheaper and enables smaller antennas (both because of the higher frequency and a more focused beam).[7] Ku band is also less vulnerable to rain fade than the Ka band frequency spectrum.

## Disadvantages

There are, however, some disadvantages of the Ku band system. Around 10 GHz is the absorption peak due to orientation relaxation of molecules in liquid water.[8] Above 10 GHz, Mie scattering takes over. The effect is a noticeable degradation, commonly known as rain fade, during heavy rain (100 mm/h).[9] This problem can be mitigated by transmitting a higher powered signal from the satellite to compensate. Therefore, the Ku band satellites typically require considerably more power to transmit than the C-band satellites.

Another weather-caused degradation called "snow fade" is not specific to the Ku band. It is due to snow or ice accumulation on a dish significantly altering its focal point.

The satellite operator's Earth station antenna requires more accurate position control when operating at Ku band due to its much narrower beam focus compared to C band for a dish of a given size. Position feedback accuracies are higher and the antenna may require a closed loop control system to maintain position under wind loading of the dish surface.

## See also

* Multifunction Advanced Data Link

## References

1. ↑ IEEE Std 521 - 2002 URL only available to IEEE members
2. ↑ Note that in the band 11.2–12 GHz the working definitions of Ku band and X band overlap; satellite communications engineers would generally regard frequencies above 11.2 GHz as being part of the Ku band.
3. ↑ "SpaceX seeks FCC permission for operating all first-gen Starlink in lower orbit" (in en-US). 2020-04-21. https://spacenews.com/spacex-seeks-fcc-permission-for-operating-all-first-gen-starlink-in-lower-orbit/.
4. ↑ Radar Detectors Glossary
5. ↑ "Radiocommunications (Communication with Space Object) Class Licence 1998". Australian Government. 2012-03-21. http://www.comlaw.gov.au/Details/F2012C00166.
6. ↑ Mirabito, M; Morgenstern, B (2004). Satellites: Operations and Applications. The New Communication Technologies (5 ed.). Burlington: Focal Press.. ISBN 978-0240805863.
7. ↑ Satellite Communications: Advantage and Disadvantages
8. ↑ Martin Chaplin: Water and Microwaves .
9. ↑ TECH-FAQ: Ku band.

## External links

* Frequency allocation information, mostly for U.S.
* Spectrum allocation chart

* v
* t
* e

Radio spectrum (ITU)

ELF
3 Hz/100 Mm
30 Hz/10 Mm

SLF
30 Hz/10 Mm
300 Hz/1 Mm

ULF
300 Hz/1 Mm
3 kHz/100 km

VLF
3 kHz/100 km
30 kHz/10 km

30 kHz/10 km
300 kHz/1 km

300 kHz/1 km
3 MHz/100 m

3 MHz/100 m
30 MHz/10 m

VHF
30 MHz/10 m
300 MHz/1 m

UHF
300 MHz/1 m
3 GHz/100 mm

SHF
3 GHz/100 mm
30 GHz/10 mm

EHF
30 GHz/10 mm
300 GHz/1 mm

THF
300 GHz/1 mm
3 THz/0.1 mm

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* v
* t
* e

Electromagnetic spectrum

* Gamma rays
* X-rays
* Ultraviolet
* Visible
* Infrared
* Microwave
* Radio

← higher frequencies longer wavelengths →

X-rays|

* soft X-ray
* hard X-ray

Ultraviolet|

* Extreme ultraviolet
* Vacuum ultraviolet
* Lyman-alpha
* FUV
* MUV
* NUV
* UVC
* UVB
* UVA

Visible (optical)|

* Violet
* Blue
* Cyan
* Green
* Yellow
* Orange
* Red

Microwaves|

* W band
* V band
* Q band
* Ka band
* K band
* Ku band
* X band
* C band
* S band
* L band

Radio|

* THF
* EHF
* SHF
* UHF
* VHF
* HF
* MF
* LF
* VLF
* ULF
* SLF
* ELF

Wavelength types|

* Microwave
* Shortwave
* Medium wave
* Longwave

* v
* t
* e

Wireless video and data distribution methods

Radio|

* Digital radio
* Radio broadcasting
* Satellite radio

Video|

* Amateur television
* Terrestrial television
* Digital
* Mobile television
* Satellite television
* Visual sensor network

Data|

* Mobile broadband
* Satellite Internet access
* Wireless broadband
* Wireless local loop

Standards|

* Advanced Wireless Services
* Digital Video Broadcasting
* Terrestrial (DVB-T)
* Satellite (DVB-S2)
* Handheld (DVB-H)
* HomeRF
* Instructional Television Fixed Service (ITFS; now known as Educational Broadband Service (EBS))
* Ku band
* Local Multipoint Distribution Service (LMDS)
* Mobile WiMAX (IEEE 802.16e)
* Mobile broadband wireless access (IEEE 802.20)
* Microwave
* Multichannel Multipoint Distribution Service (MMDS; now known as Business Radio Service (BRS))
* Multipoint Video Distribution System (MVDS or DVB-MS)
* MVDDS
* Multimedia Broadcast Multicast Service (3G MMMS)
* UWB (IEEE 802.15.3)
* Wi-Fi (IEEE 802.11)
* WiMAX (IEEE 802.16)
* WRAN (IEEE 802.22)
* Wireless USB
* 3GPP Long Term Evolution (LTE)
* 4G
* 5G

* v
* t
* e

Telecommunications

History|

* Beacon
* Broadcasting
* Cable protection system
* Cable TV
* Communications satellite
* Computer network
* Data compression
* audio
* DCT
* image
* video
* Digital media
* Internet video
* online video platform
* social media
* streaming
* Drums
* Edholm's law
* Electrical telegraph
* Fax
* Heliographs
* Hydraulic telegraph
* Information Age
* Information revolution
* Internet
* Mass media
* Mobile phone
* Smartphone
* Optical telecommunication
* Optical telegraphy
* Pager
* Photophone
* Prepaid mobile phone
* Radio
* Radiotelephone
* Satellite communications
* Semaphore
* Semiconductor
* device
* MOSFET
* transistor
* Smoke signals
* Telecommunications history
* Telautograph
* Telegraphy
* Teleprinter (teletype)
* Telephone
* The Telephone Cases
* Television
* digital
* streaming
* Undersea telegraph line
* Videotelephony
* Whistled language
* Wireless revolution

Pioneers|

* Nasir Ahmed
* Edwin Howard Armstrong
* Mohamed M. Atalla
* John Logie Baird
* Paul Baran
* John Bardeen
* Alexander Graham Bell
* Tim Berners-Lee
* Jagadish Chandra Bose
* Walter Houser Brattain
* Vint Cerf
* Claude Chappe
* Yogen Dalal
* Donald Davies
* Lee de Forest
* Philo Farnsworth
* Reginald Fessenden
* Elisha Gray
* Oliver Heaviside
* Erna Schneider Hoover
* Harold Hopkins
* Internet pioneers
* Bob Kahn
* Dawon Kahng
* Charles K. Kao
* Narinder Singh Kapany
* Hedy Lamarr
* Innocenzo Manzetti
* Guglielmo Marconi
* Robert Metcalfe
* Antonio Meucci
* Jun-ichi Nishizawa
* Radia Perlman
* Alexander Stepanovich Popov
* Johann Philipp Reis
* Claude Shannon
* Henry Sutton
* Nikola Tesla
* Camille Tissot
* Alfred Vail
* Charles Wheatstone
* Vladimir K. Zworykin

Transmission
media|

* Coaxial cable
* Fiber-optic communication
* optical fiber
* Free-space optical communication
* Molecular communication
* Radio waves
* wireless
* Transmission line
* data transmission circuit
* telecommunication circuit

Network topology
and switching|

* Bandwidth
* Links
* Nodes
* terminal
* Network switching (circuit
* packet)
* Telephone exchange

Multiplexing|

* Space-division
* Frequency-division
* Time-division
* Polarization-division
* Orbital angular-momentum
* Code-division

Networks|

* ARPANET
* BITNET
* Cellular network
* Computer
* CYCLADES
* Ethernet
* FidoNet
* Internet
* Internet2
* ISDN
* LAN
* Mobile
* NGN
* NPL network
* Public Switched Telephone
* Radio
* Telecommunications equipment
* Television
* Telex
* WAN
* Wireless network
* World Wide Web

* Category
* Outline
* Portal
* Commons

* v
* t
* e

Analog and digital audio broadcasting

Terrestrial|

| Radio modulation|

* AM
* FM
* COFDM

|

Frequency allocations|

* LW (LF)
* MW (MF)
* SW (HF)
* VHF (low / mid / high)
* L band (Ultra high frequency

Digital systems|

* CAM-D
* DAB/DAB+
* DRM/DRM+
* FMeXtra
* HD Radio
* CDR
* DVB-T2 Lite

Satellite|

| Frequency allocations|

* C band
* Ku band
* L band
* S band

|

Digital systems|

* ADR
* DAB-S
* DVB-SH
* S-DMB
* SDR

Commercial radio providers|

* Sirius XM Holdings
* SiriusXM Canada

Codecs|

* AAC
* AMR-WB+
* HDC
* HE-AAC
* MPEG-1 Audio Layer II

Subcarrier signals|

* AMSS
* DirectBand
* PAD
* RDS/RBDS
* SCA/SCMO
* DARC

Related topics

Technical (audio)|

* Audio data compression
* Audio signal processing

Technical (AM stereo formats)|

* Belar
* C-QUAM
* Harris
* Kahn-Hazeltine
* Magnavox

Technical (emission)|

* AM broadcasting
* AM expanded band
* Cable radio
* Digital radio
* Error detection and correction
* FM broadcast band
* FM broadcasting
* Multipath propagation
* Shortwave relay station

Cultural|

* History of radio
* International broadcasting

* Comparison of radio systems

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