Super high frequency
Frequency range | 3 to 30 GHz |
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Wavelength range | 10 to 1 cm |
Related bands |
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Super high frequency (SHF) is the
Frequencies in the SHF range are often referred to by their
Propagation
The
Small amounts of microwave energy are randomly scattered by water vapor molecules in the
Antennas
The
The wavelengths are also small enough that SHF waves can be focused into narrow beams by
Waveguide
At microwave frequencies, the types of cable (
Advantages
SHF frequencies occupy a "sweet spot" in the radio spectrum which is currently being exploited by many new radio services.[3] They are the lowest frequency band where radio waves can be directed in narrow beams by conveniently sized antennas so they do not interfere with nearby transmitters on the same frequency, allowing frequency reuse. On the other hand, they are the highest frequencies which can be used for long distance terrestrial communication; higher frequencies in the EHF (millimeter wave) band are highly absorbed by the atmosphere, limiting practical propagation distances to one kilometer or less. The high frequency gives microwave communication links a very large information-carrying capacity (bandwidth). In recent decades many new solid state sources of microwave energy have been developed, and microwave integrated circuits for the first time allow significant signal processing to be done at these frequencies. Sources of EHF energy are much more limited and in an earlier state of development.
See also
- Knife-edge effect
- Microwave burn
References
- ^ Freedman, S. (September 1946). "Two-way radio for everyone" (PDF). Radio News. 36 (3). New York: Ziff-Davis Publications: 25–27. Retrieved March 24, 2014. This article from the beginning of the microwave era predicted the future value of microwaves for point-to-point communication.
- ISBN 0471743682.
- ISBN 1316175774.
External links
- Tomislav Stimac, "Definition of frequency bands (VLF, ELF... etc.)". IK1QFK Home Page (vlf.it).
- Inés Vidal Castiñeira, "Celeria: Wireless Access To Cable Networks"