When talking about RF communication or other technology that uses radio waves, it's frequently useful to talk in terms of bands or blocks of the RF spectrum. One way to break up the whole RF spectrum is specified by the ITU: the International Telecommunication Union. The ITU is a United Nations agency that helps countries coordinate how the radio spectrum is used for communication worldwide.
Why are there ITU bands?
There are a few reasons to defer to a United Nations agency for designating areas of the RF spectrum.
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Global coordination: A single set of names makes it easier for governments, satellite operators, and international communication organizations to talk the same language.
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Broad coverage: The ITU system stretches from below 300 Hz up to 300 GHz. This covers the range of generally useful frequencies for communication.
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Similar Applications: Different parts of the RF spectrum have different strengths and weaknesses, the ITU bands generally group these applications together, without being too restrictive.
What are the ITU bands?
The ITU frequency bands are numbered based on a formula:
Band N covers frequencies 0.3x10N to 3x10N Hz
So, Band 6 covers frequencies 0.3x106 to 3x106 Hz, or 300 kHz to 3 MHz.
However, most people refer to the ITU bands based on their symbols which are ELF, VHF, UHF, etc. We therefore use those symbols in this guide, but we also denote the actual band numbers.
The ITU bands, explained
ELF (Extremely Low Frequency)
Band -1 — 30 mHz to 300 mHz
Band 0 — 300 mHz to 3 Hz
Band 1 — 3 Hz to 30 Hz
Band 2 — 30 Hz to 300 Hz (sometimes called SLF, Super Low Frequency)
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Typical uses: Scientific research such as atmospheric science and seismology.
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Traits: These frequencies are typically generated by natural phenomena and pass through almost anything.
- These bands are sometimes not included when talking about ITU bands as they're not used for general communication, but the grouping is helpful for scientists working at these frequencies.
ULF (Ultra Low Frequency)
Band 3 —300 Hz to 3 kHz; 1,000 km to 100 km wavelengths
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Typical uses: Scientific research of the atmosphere, underground mine communication.
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Traits: Signals easily travel through the earth.
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Communicating through the earth with electrical signals is called "earth-mode" and was developed during WWI.
VLF (Very Low Frequency)
Band 4 — 3 kHz to 30 kHz; 100 km to 10 km wavelengths
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Typical uses: Navigation beacons, military communications, submarine communication.
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Traits: Signals can travel some distance through rock and water. They hug the ground and can bounce off the ionosphere enabling global communication.
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While early transoceanic communication used this band, it cannot transmit information quickly so modern implementations use advanced compression.
LF (Low Frequency)
Band 5 — 30 kHz to 300 kHz; 10 km to 1 km wavelengths
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Everyday uses: AM radio broadcasting (in Europe and parts of Asia), amateur (ham) radio, navigation beacons, time synchronization.
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Traits: Like VLF, these low frequencies hug the Earth’s surface (called ground wave) and travel huge distances.
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This band is commonly used to synchronize clocks. In the US, the National Institute of Standards and Technology (NIST) broadcasts time on the station WWVB at 60 kHz from their headquarters in Colorado.
MF (Medium Frequency)
Band 6 — 300 kHz to 3 MHz; 1 km to 100 m wavelengths
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Everyday uses: AM radio broadcasting, some maritime and aeronautical beacons.
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Traits: Still travels long distances, especially at night when signals bounce off the atmosphere.
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The AM radio station you tune to is simply the frequency of the broadcast in kHz. For example, WTAM 1100 here in Cleveland broadcasts at 1100 kHz, or 1.1 MHz.
HF (High Frequency)
Band 7 — 3 MHz to 30 MHz; 100 m to 10 m wavelengths
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Everyday uses: Shortwave radio, amateur (ham) radio, international broadcasting.
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Traits: Can bounce off the ionosphere (called skywave), making global communication possible without satellites, but it's subject to a variety of factors like time of day, solar activity, etc.
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This is a popular band for amateur radio because of the long distances possible.
VHF (Very High Frequency)
Band 8 — 30 MHz to 300 MHz; 10 m to 1 m wavelengths
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Everyday uses: FM radio, over-the-air TV, Land Mobile Radio and marine communications.
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Traits: Signals travel in straight lines (“line of sight”) and are blocked by hills and mountains.
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FM radio sits in the VHF band (88–108 MHz).
UHF (Ultra High Frequency)
Band 9 — 300 MHz to 3 GHz; 1 m to 10 cm wavelengths
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Everyday uses: Wi-Fi, Bluetooth, over-the-air TV, mobile phones, walkie-talkies, two-way radios for public safety and other short-range communication.
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Traits: Good penetration through buildings and objects, but cannot go over the horizon.
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Your kitchen microwave operates in this band (at 2.4 GHz) because water absorbs energy at that frequency.
SHF (Super High Frequency)
Band 10 — 3 GHz to 30 GHz; 10 cm to 1 cm wavelengths
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Everyday uses: Radar, satellite communication, point-to-point links/relays, 5G cellular.
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Traits: Signals are blocked by (or bounce off) vehicles and buildings, but can travel vast distances in straight lines.
- Most commercial satellite communication is in this band.
EHF (Extremely High Frequency)
Band 11 — 30 GHz to 300 GHz; 10 mm to 1 mm
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Everyday uses: Radio astronomy, point-to-point communication, military and police radar, security screening, mmWave 5G cellular.
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Traits: The gasses in the atmosphere absorb certain frequencies in this band and raindrops can diffract them, but they otherwise travel in straight lines.
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Automotive radar is increasingly in this band (typically 77 GHz) due to the increased possible resolution.
Higher Bands
These bands don't have recognized symbols, though some like THF (Tremendously High Frequencies) have been suggested.
Band 12 — 300 GHz to 3 THz
Band 13 — 3 THz to 30 THz
Band 14 — 30 THz to 300 THz
Band 15 — 300 THz to 3 PHz
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Everyday uses: Scientific research in materials, nuclear science, optical communication, medical imaging
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Traits: These bands leave the typical "Radio" part of the RF spectrum and become light.
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Visible light is in band 15 (~400 THz to ~790 THz).
Quick Reference Chart
| ITU Band | Symbol | Frequency Range | Name | Common Use |
|---|---|---|---|---|
| −1 | ELF | 30 to 300 mHz | Extremely Low Frequency | Scientific research |
| 0 | ELF | 300 mHz to 3 Hz | Extremely Low Frequency | Scientific research |
| 1 | ELF | 3 to 30 Hz | Extremely Low Frequency | Scientific research |
| 2 | ELF (SLF) | 30 to 300 Hz | Extremely Low Frequency (Super Low Frequency) | Scientific research |
| 3 | ULF | 300 Hz to 3 kHz | Ultra Low Frequency | Scientific research |
| 4 | VLF | 3 to 30 kHz | Very Low Frequency | Navigation, military communication |
| 5 | LF | 30 to 300 kHz | Low Frequency | Navigation, specialty communication |
| 6 | MF | 300 kHz to 3 MHz | Medium Frequency | AM radio |
| 7 | HF | 3 to 30 MHz | High Frequency | Shortwave radio |
| 8 | VHF | 30 to 300 MHz | Very High Frequency | FM radio, short-range communication |
| 9 | UHF | 300 MHz to 3 GHz | Ultra High Frequency | Wi-Fi, cellular, commercial communication |
| 10 | SHF | 3 to 30 GHz | Super High Frequency | Radar, cellular, satellite communication |
| 11 | EHF | 30 to 300 GHz | Extremely High Frequency | Cellular, scientific research |
| 12 | (THF) | 300 GHz to 3 THz | (Tremendously High Frequency) | Scientific research |
| 13 | 3 to 30 THz | Scientific research | ||
| 14 | 30 to 300 THz | Scientific research | ||
| 15 | 300 THz to 3 PHz | Scientific research |
FAQs
How do I measure a frequency band?
Bird Wattmeters and RF power sensors can be used to measure the forward and reflected power in an RF transmission line across the HF, VHF, and UHF bands.
The Bird SignalHawk spectrum analyzer can be used to measure over-the-air power with an antenna as well as analyze the spectral content of a signal in the VLF, LF, MF, HF, VHF, UHF, and SHF bands (9 kHz to 7.5 GHz).
Where are the 5G bands?
Cellular 5G is spread across UHF, SHF, and EHF, or bands 9, 10, and 11. The 5G standard uses many small, defined frequency ranges, but they are grouped into frequency ranges FR1 and FR2.
| FR1 | 410 MHz to 7.125 GHz |
| FR2 | 24.25 GHz to 71 GHz |
| FR3 (proposed) | 7.125 GHz to 24.25 GHz |
Need to generate 5G cellular signals? Check out the Bird GenHawk GH-60!
Where are the satellite bands?
Satellite communication generally takes place in the UHF and EHF bands. However, for better distinction, most satellite operators use IEEE frequency band names, which have more subdivisions at higher frequencies:
| IEEE Band | Frequency Range | ITU Symbol | Common Applications |
|---|---|---|---|
| L | 1–2 GHz | UHF | GPS, mobile, satellite phones |
| S | 2–4 GHz | UHF/EHF | Wi-Fi, Bluetooth, radar, microwave ovens |
| C | 4–8 GHz | EHF | Satellite TV/internet, 5G |
| X | 8–12 GHz | EHF | Military radar, satellite communications |
| Ku | 12–18 GHz | EHF | Satellite TV/internet |
| K | 18–27 GHz | EHF | Police radar, vehicle radar |
| Ka | 27–40 GHz | EHF/(THF) | Starlink, high-speed satellite internet |
| V | 40–75 GHz | (THF) | 5G trials, tower backhaul |
| W | 75–110 GHz | (THF) | Advanced radar, security scanners |
| mmWave | 30–300 GHz | (THF) | 5G, automotive radar, research |
What is mmWave?
mmWave, or millimeter wave, is the name of the EHF band, covering 30 to 300 GHz. It's called the mmWave band because the radio waves in this band range from 1 to 10 mm in wavelength. The other bands also have names based on their wavelengths. These names typically use older, uncommon SI prefixes like Hecto- and Deci- by convention. The prefix Myria- is obsolete, but still used by some working in the VLF band.
| Band | Symbol | Wavelength Name | Wavelengths (in common prefixes) |
| Band -1 | ELF | Gigameter waves | 1x107 to 1x108 km |
| Band 0 | ELF | Hectomegameter waves | 1x106 to 1x107 km |
| Band 1 | ELF | Decamegameter waves | 1x105 to 1x106 km |
| Band 2 | ELF(SLF) | Megameter waves | 1x104 to 1x105 km |
| Band 3 | ULF | Hectokilometer waves | 100 to 1,000 km |
| Band 4 | VLF | Myriameter waves | 10 to 100 km |
| Band 5 | LF | Kilometer waves | 1 to 10 km |
| Band 6 | MF | Hectometer waves | 100 to 1,000 m |
| Band 7 | HF | Decameter waves | 10 to 100 m |
| Band 8 | VHF | Meter waves | 1 to 10 m |
| Band 9 | UHF | Decimeter waves | 10 to 100 cm |
| Band 10 | SHF | Centimeter waves | 1 to 10 cm |
| Band 11 | EHF | Millimeter waves | 1 to 10 mm |
| Band 12 | (THF) | Decimillimeter waves | 100 to 1,000 µm |
| Band 13 | Centimillimeter waves | 10 to 100 µm | |
| Band 14 | Micrometer waves | 1 to 10 µm | |
| Band 15 | Decimicrometer waves | 10 to 1,000 nm |
What does the FCC allocate? Why?
In the United States, the FCC regulates the how the RF spectrum is used. Other national and international organizations are responsible for this important job in other parts of the world. The FCC regulates frequencies between 8.3 kHz and 275 GHz, VLF to EHF. Outside that range, natural phenomena and technical limits make regulation impractical.
Within the range the FCC regulates, they allocate blocks or bands of the spectrum for specific uses. The RF spectrum is an extremely limited resource that has served vital roles since the discovery of radio communication, so standardized rules and cooperation are needed to prevent interference and make sure the spectrum can be used in a way that's most practical.
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