mm wave or EHF (Extremely high frequency) is the highest radio frequency band in practical use today. EHF includes frequencies from 30 to 300 gigahertz. mm wave is the next band, above “microwave”.
It is because this band has a wavelength of between 1 and 10mm that it has given rise to the name “millimeter band” or “millimetre wave”, also called mmwave or mm wave. The frequencies in this band are very susceptible to attenuation due to rain or snow or fog (depending on which part of the band). Because of this they are not used for long distances, but they are excellent in some short distance applications, and of course re-use of frequencies in the mmwave band is common
In particular, signals in the 57–64 GHz region can be highly attenuated by resonance of the oxygen molecule.
mm wave Communication makes for small parts
Because of the small wavelength, smaller antennas may achieve very tight beamwidths, which makes re-using frequencies easier, and network design and interference management much easier.
The picture at right depicts a selection of waveguide, which is used due to the lower propagation capability of coaxial cable at these frequencies. Quite simply, a waveguide is a structure which guides electromagnetic waves or sound waves. They are primarily used in interconnection situations such as between an antenna and a mm wave radio or transceiver.
The manufacture of mm wave components is a highly precise operation, and most manufacturing remains in the United States. Several companies make mm wave components in the US, including Millitech, Farran Technology, Mercury Systems, Quinstar Technology, MI-Wave, Spacek Labs, Aerowave Inc., Cobham Defence Systems, and many others.