Mode swirl chamber

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A mode swirl chamber is a measurement and test environment in the field of electromagnetic compatibility according to the IEC 61000-4-21 standard . Similar to an absorber chamber , a GTEM cell or a TEM cell, the chamber is used either to measure the radiated emitted interference from an electrical or electronic device or to test the immunity of a device to electromagnetic fields.

View into a mode swirl chamber with a motorcycle as a test object. At the back left a vertical mode stirrer, at the back right a logarithmic-periodic broadband antenna and a small horn antenna, on the right on the vertical rods there are four sensors for measuring the electric field strength.

A mode swirl chamber is distinguished from an absorber chamber by its high quality . The quality factors should, if possible, assume values ​​greater than 10,000, so that very high field strengths can be generated with a comparatively low feed-in power. For testing purposes, the electromagnetic fields are entered more or less non-directionally into the test chamber by means of antennas and are reflected as completely as possible on the metal walls of the chamber.

A reverberation chamber has a mechanical mode stirrer ( English mode Stirrer ) which periodically varies the electromagnetic boundary conditions within the measurement environment. In this way, the electromagnetic field strength distribution in the test volume changes continuously, so that the test object is evenly illuminated, or in the case of an emission measurement by the receiving antenna inside the chamber, the total power radiated by the test object is recorded without any particular influence of the directional characteristics of the test object. The IEC 61000-4-21 standard describes the use of the mode swirl chamber.

Test environments made of conductive textiles work according to the same principle, which - built around the test or measurement object - are moved mechanically during the input of electromagnetic field energy in order to vary the electromagnetic field in this way.

literature

  • Krauthäuser, Hans Georg: "Basics and Applications of Modenwirbelungskammern", Res Elictricae Magdeburgenses, Volume 17, 2007, ISBN 978-3-929757-43-9 (ISBN was apparently assigned several times. The data set in the German National Library can be found here )
  • Kürner, Wolfgang: "Measurement of radiated emissions and housing shield attenuation in the mode swirl chambers " Tenea Verlag 2003, ISBN 3-936582-57-2
  • Hillgärtner, Michael: "Hohlraumresonanzgüte in Modenwirbelungskammern" Der Andere Verlag 2007, ISBN 978-3-89959-679-3
  • Schwab, Adolf, Kürner, Wolfgang: "Electromagnetic Compatibility" Springer-Verlag 2007, 5th edition, ISBN 978-3-540-42004-0 , page 303

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