High frequency technology
The high-frequency technology , abbreviated RF technology , is a branch of electrical engineering and the engineering sciences . An electrical engineer who specializes in this is called a high frequency engineer , or HF engineer for short . Other people who deal with this can generally be described as high frequency technicians , or RF technicians for short .
HF technology deals with electromagnetic waves , in particular with methods, devices and systems for their generation, the theory and practice of wave propagation and the reception of waves. Important areas are antenna technology and high frequency measurement technology .
Practical application finds the RF technology in many areas of daily life, such as in mobile phones or smartphones , with radio and television , in traffic- and safety-related applications, such as the aeronautical , marine radio and police radio , the air surveillance using radars and even the security check at airports using body scanners , as well as radio remote controls and radio remote controls as well as in many other areas of science and technology, for example in medicine for diagnosis and therapy (e.g. high-frequency thermotherapy ), in non-destructive material testing , or as ground penetrating radar in archeology and geophysics .
The frequency range of high frequency technology is not defined uniformly. A narrow definition of the International Telecommunication Union restricted it to 3 MHz to 30 MHz, so the traditionally as shortwave designated frequency band , and refers to the overlying frequency bands for 30 MHz to 300 MHz as the VHF ( Very High Frequency ; German: very high frequency) in In the past, Germans often referred to it as UKW (ultra short wave) , for 300 MHz to 3 GHz as UHF ( ultra high frequency ; German: ultra high frequency), for 3 GHz to 30 GHz as SHF ( super high frequency ; German: super high frequency) and for 300 GHz to 3 THz as EHF ( Extremely High Frequency ; German: extremely high frequency). Another band has recently been added, namely for 3 THz to 30 THz as THF ( Tremendously High Frequency ; German: enormously high frequency). A broad interpretation of the term high frequency allows it to be used for all of the frequency bands mentioned , i.e. from around 3 MHz to around 30 THz or even more, thus for a large part of the electromagnetic spectrum as a whole.
In contrast to direct current technology, HF technology deals with alternating currents , where traditionally the different areas of work have been subdivided according to the characteristic properties of alternating current, namely its frequency , into low frequency technology (LF technology), sometimes, but very rarely, "medium frequency technology “ , Then high-frequency technology, and then sometimes the high-frequency technology used . (For example, there used to be " chairs for high and maximum frequency technology" at some universities , although it makes sense to dispense with the use of the superlative.) In practice, only the terms LF technology and HF technology are left today, with the limit around 3 MHz, but lower can also be assumed. For example, the principles known from HF technology also apply below 3 MHz, i.e. also in the medium wave and long wave range . Like the lower one, the upper frequency limit of the HF technology is not sharply drawn. Usually one also counts the millimeter wave range , i.e. frequencies up to 300 GHz. One often hears the term microwave technology , for example in connection with the popular microwave ovens . This trivial name originally comes from American English ( microwaves in English: microwaves ) and means a sub-range of the high frequency range, approximately from 300 MHz to 300 GHz. Microwave technology can be understood as a sub-area of high frequency technology.
Important areas of high frequency technology are:
- Line theory (see also: Smith diagram and waveguide )
- Components such as time-of- flight tubes or directional couplers
- Antennas such as parabolic antennas and yagi antennas
- Transmission and reception technology (see also: heterodyne receiver )
- Modulation method
- High frequency measurement technology
Famous RF technicians
- Heinrich Hertz (1857–1894) achieved the first experimental evidence and the transmission of electromagnetic waves from a transmitter to a receiver in the 1880s.
- Nikola Tesla (1856–1943) experimented with high-frequency alternating currents in the 1890s, also with regard to the possibility of wireless energy transmission .
- Alexander Popow (1859–1906) initially bridged 190 meters wirelessly in 1895 and increased this to 112 kilometers by 1900.
- Guglielmo Marconi (1874–1937) is considered to be the pioneer of wireless communication. He achieved the first transatlantic transmission in 1903.
- Phillip Smith (1905–1987) developed the diagram named after him in 1937 , one of the most important drawing aids in HF technology.
- Jürgen Detlefsen, Uwe Siart: Fundamentals of high frequency technology , updated edition, Oldenbourg Wissenschaftsverlag , Munich 2012. ISBN 3-486-70891-0 .
- H. Meinke, FW Gundlach : Pocket book of high frequency technology Volume 1 - Basics. 5th edition, Springer, Berlin 1992. ISBN 3-540-54714-2 .
- H. Meinke, FW Gundlach: Pocket book of high frequency technology Volume 2 - Components. 5th edition, Springer, Berlin 1992. ISBN 3-540-54715-0 .
- H. Meinke, FW Gundlach: Pocket book of high frequency technology Volume 3 - Systems. 5th edition, Springer, Berlin 1992. ISBN 3-540-54716-9 .
- Ulrich L. Rohde, Matthias Rudolph: RF / Microwave Circuit Design for Wireless Applications , 2nd Edition John Wiley & Sons December 2012. ISBN 978-0-470-90181-6
- George D. Vendelin, Anthony M. Pavio, Ulrich L. Rohde: Microwave Circuit Design Using Linear and Nonlinear Techniques , 2nd Edition, John Wiley & Sons, July 2005, ISBN 978-0-471-41479-7
- V.431: Nomenclature of the frequency and wavelength bands used in telecommunications. ITU , accessed June 18, 2015 .