Radio frequency
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:
| Band name | Abbr | ITU band | Frequency | Wavelength |
|---|---|---|---|---|
| < 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 |
| Low frequency | LF | 5 | 30–300 kHz | 10 km – 1 km |
| Medium frequency | MF | 6 | 300–3000 kHz | 1 km – 100 m |
| High frequency | HF | 7 | 3–30 MHz | 100 m – 10 m |
| Very high frequency | VHF | 8 | 30–300 MHz | 10 m – 1 m |
| Ultra high frequency | UHF | 9 | 300–3000 MHz | 1 m – 100 mm |
| Super high frequency | SHF | 10 | 3–30 GHz | 100 mm – 10 mm |
| Extremely high frequency | EHF | 11 | 30–300 GHz | 10 mm – 1 mm |
| Above 300 GHz | < 1 mm |
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).
Table of contents |
Named frequency bands
- Band III – 174–245 MHz
- ISM band......specific frequencies vary
Microwave (IEEE US)
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
See also
|
Radio spectrum |
| Electromagnetic Spectrum
Radio waves | Microwave | Infrared | Optical spectrum | Ultraviolet | X-ray | Gamma ray Visible: Red | Orange | Yellow | Green | Blue | Indigo | Violet |
External links
Categories: Radio spectrum