Radio Frequency (RF) Radiation – Introduction
Radio Frequency (RF) waves are part of the electromagnetic spectrum and their wave lengths are longer than those of the infra-red range. According to the International Telecommunications Union (ITU) classification, the range of radio frequencies is wide, and defined as 3KHZ-300GHz (or wave lengths of 1 mm – 100 Km). The International Committee for Non-Ionizing Radiation Protection (ICNIRP) divides the frequencies into ranges according to their effects on health, and considers the range of 100KHz - 300GHz as a High Frequency range.
Radio waves are formed naturally on earth, for instance by lightning, or in space - by astronomical bodies. Radio waves are created by man for a variety of uses. Examples are: public broadcasting stations of radio and TV, transmission sites for mobile communications (cellular and other) and portable wireless devices (cellular and other), radar stations and navigation systems, communication satellites, wireless computer networks, and domestic appliances, such as the microwave oven.
The range of radio frequencies is generally divided into frequency bands, according to the different uses, as defined by the International Communications Union (ITU).
A detailed list of frequencies and principal uses of radio frequency bands (RF bands) in the electromagnetic spectrum appears in the Table below, based on the ITU classification (on the ITU's web site).
Nomenclature of frequencies and principal uses of radio waves*
|
Band frequencies |
Band group ITU |
Frequency range |
Ranges of wave lengths |
Examples of uses and characteristics |
|
VLF |
4 | 3 - 30 kHz | 10-100 Km | Navigation, time signals, submarine communication, wireless heart monitoring, geophysics |
| LF Low Frequency |
5 | 30 - 300 kHz | 1-10 Km | Navigation, time signals, long-wave AM transmission (Europe, part of Asia), Radio frequency identification (RFID), amateur radio |
| MF Medium Frequency |
6 | 300 kHz - 3 MHz | 100-1000 m | Medium wave AM transmission, amateur radio, earthquakes, avalanches |
| HF High Frequency |
7 | 3 - 30 MHz | 10-100 m (short wave) |
Short wave transmission, amateur and public radio, airways communication beyond the horizon, Radio frequency identification (RFID), beyond horizon radar, sky waves, mobile marine communication |
| VHF Very High Frequency |
8 | 30 - 300 MHz | 1-10 m | FM radio, TV transmission, earth-to-aircraft or aircraft to aircraft communication within the line of vision, mobile marine or ground communication, amateur radio, weather radio |
| UHF Ultra High Frequency |
9 | 300 MHz - 3 GHz | 100 mm – 1m |
Classification according to principal generations of communications technologies:
(1) 2nd generation (4) 4th generation , LTE , etc
TV transmission, microwave ovens, microwave installations and communication, radio astronomy, cellular devices, wireless local area network (LAN), Bluetooth, global positioning system (GPS), two-way radio Family Radio Service (FRS) and General Mobile Radio Service (GMRS), amateur radio |
| SHF Super High Frequency |
10 | 3 - 30 GHz | 1 - 10 cm |
|
| EHF Extremely High Frequency |
11 | 30 - 300 GHz | 1 - 10 mm | Radio astronomy, high-frequency microwave relay stations, distance sensing at microwave frequency, amateur radio, directed energy weapons, millimeter wave scanner |
|
*Source: Recommendation ITU-R V.431-7, Nomenclature of the Frequency and Wavelength Bands used in Telecommunications |
References
- Poole I. Basic Radio: Principles and Technology. 1998; Newnes.
- Barclay LW. Propagation of Radio Waves. 2nd Edition, IET Electromagnetic Waves Series 502. 2003.
- ITU - International Telecommunications Union website
- ICNIRP - International Committee for Non Ionizing Radiation Protection website
16.11.15
