Radio frequency
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Atmospheric_electromagnetic_transmittance_or_opacity.jpg
Radio frequency, or RF, refers to that portion of the electromagnetic spectrum in which electromagnetic waves can be generated by alternating current fed to an antenna. Such frequencies account for the following parts of the spectrum shown in the table below.
Note: above 300 GHz, the absorption of electromagnetic radiation by Earth's atmosphere is so great that the atmosphere is effectively opaque to higher frequencies of electromagnetic radiation, until the atmosphere becomes transparent again in the so-called infrared and optical window frequency ranges.
The ELF, SLF, ULF, and VLF bands overlap the AF (audio frequency) spectrum, which is approximately 20–20,000 Hz. However, sounds are transmitted by atmospheric compression and expansion, and not by electromagnetic energy.
Electrical connectors designed to work at radio frequencies are known as RF connectors. RF is also the name of a standard audio/video connector, also called BNC (Bayonet Neill-Concelman).
| Band name | Abbr | ITU band | Frequency Wavelength | Example uses |
|---|---|---|---|---|
| < 3 Hz > 100,000 km | ||||
| Extremely low frequency | ELF | 1 | 3–30 Hz 100,000 km – 10,000 km | |
| Super low frequency | SLF | 2 | 30–300 Hz 10,000 km – 1000 km | |
| Ultra low frequency | ULF | 3 | 300–3000 Hz 1000 km – 100 km | |
| Very low frequency | VLF | 4 | 3–30 kHz 100 km – 10 km | Military communication |
| Low frequency | LF | 5 | 30–300 kHz 10 km – 1 km | Navigation, time signals, AM longwave broadcasting |
| Medium frequency | MF | 6 | 300–3000 kHz 1 km – 100 m | AM broadcasts |
| High frequency | HF | 7 | 3–30 MHz 100 m – 10 m | Shortwave broadcasts and amateur radio |
| Very high frequency | VHF | 8 | 30–300 MHz 10 m – 1 m | FM and television broadcasts |
| Ultra high frequency | UHF | 9 | 300–3000 MHz 1 m – 100 mm | television broadcasts |
| Super high frequency | SHF | 10 | 3–30 GHz 100 mm – 10 mm | microwave devices, mobile phones, wireless LAN |
| Extremely high frequency | EHF | 11 | 30–300 GHz 10 mm – 1 mm | |
| Above 300 GHz < 1 mm |
| Contents |
Named frequency bands
- Band III - 174–245 MHz
- ISM band......specific frequencies vary
Microwave (IEEE US)
| Band | Frequency range |
|---|---|
| L band | 1 to 2 GHz |
| S band | 2 to 4 GHz |
| C band | 4 to 8 GHz |
| X band | 8 to 12 GHz |
| Ku band | 12 to 18 GHz |
| K band | 18 to 26 GHz |
| Ka band | 26 to 40 GHz |
| V band | 40 to 75 GHz |
| W band | 75 to 111 GHz |
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See also
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Radio spectrum |
| Electromagnetic Spectrum
Radio waves | Microwave | Terahertz radiation | Infrared | Optical spectrum | Ultraviolet | X-ray | Gamma ray Visible: Red | Orange | Yellow | Green | Blue | Indigo | Violet |
External links
- Radio and light waves conversion: frequency to wavelength and vice versa (http://www.sengpielaudio.com/calculator-wavelength.htm)
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