Extremely high frequency

Extremely high frequency
Extremely high frequency
Frequency range
30 to 300 GHz
Wavelength range
10–1 mm
Related bands
  • K / L / M (NATO)
  • Ka / V / W / mm (IEEE)
Millimetre band (IEEE)
Frequency range
110 to 300 GHz
Wavelength range
2.73 to 1 mm
Related bands
EHF (IEEE)

Extremely high frequency is the International Telecommunication Union designation for the band of radio frequencies in the electromagnetic spectrum from 30 to 300 gigahertz (GHz). It lies between the super high frequency band and the far infrared band, the lower part of which is the terahertz band. Radio waves in this band have wavelengths from ten to one millimeter, so it is also called the millimeter band and radiation in this band is called millimeter waves, sometimes abbreviated MMW or mmWave. Millimeter-length electromagnetic waves were first investigated by Jagadish Chandra Bose, who generated waves of frequency up to 60 GHz during experiments in 1894–1896.[1]

Compared to lower bands, radio waves in this band have high atmospheric attenuation: they are absorbed by the gases in the atmosphere. Absorption increases with frequency until at the top end of the band the waves are attenuated to zero within a few meters. Absorption by humidity in the atmosphere is significant except in desert environments, and attenuation by rain (rain fade) is a serious problem even over short distances. However the short propagation range allows smaller frequency reuse distances than lower frequencies. The short wavelength allows modest size antennas to have a small beam width, further increasing frequency reuse potential. Millimeter waves are used for military fire-control radar, airport security scanners, short range wireless networks, and scientific research.

In a major new application of millimeter waves, certain frequency ranges near the bottom of the band are being used in the newest generation of cell phone networks, 5G networks.[2] The design of millimeter-wave circuit and subsystems (such as antennas, power amplifiers, mixers and oscillators) also presents severe challenges to engineers due to semiconductor and process limitations, model limitations and poor Q factors of passive devices.[3]

  1. ^ "Milestones: First Millimeter-wave Communication Experiments by J.C. Bose, 1894-96". List of IEEE milestones. Institute of Electrical and Electronics Engineers. 14 June 2022.
  2. ^ User Equipment (UE) radio transmission and reception; Part 3: Range 1 and Range 2 Interworking operation with other radios (PDF) (Technical Specification). 3GPP TS 38.101-3 version 15.2.0 Release 15. ETSI. July 2018. p. 11. Retrieved 5 December 2019.
  3. ^ du Preez, Jaco; Sinha, Saurabh (2017). Millimeter-Wave Power Amplifiers. Springer. pp. 1–35. ISBN 978-3-319-62166-1.