Field strength meter

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A field intensity meter (also: radiometer ; English field strength meter ) is a measuring device for electromagnetic fields measurement , in particular for the metrological evaluation of the electromagnetic compatibility ( EMC testing ).

A distinction is made between measuring devices for measuring the field strength of electric fields ( electric field strength ) and for measuring magnetic fields ( magnetic field strength ).

Basics

In the far field of antennas , electrical (E-field) and magnetic field strength (H-field) are linked to one another via the wave resistance of the vacuum , more precisely the wave resistance in air . So it is sufficient to measure a quantity, E-field or H-field. The other is then calculated. In the near field, however, the situation is more complicated and it is advisable to measure both components individually.

For this purpose, most radiation measuring devices have different field probes as a supplement to a uniform basic device that contains control elements , evaluation electronics and display . These cover different frequency ranges and are used to measure the E-field or the H-field. In principle, E-field probes are mostly implemented as small dipole antennas and H-field probes as small loop antennas .

A great help for practical use is that the probes - in contrast to the simple antennas mentioned - allow measurement independent of direction. One speaks of “ isotropic probes”. This is achieved by combining not just one small antenna, but three orthogonally arranged specimens in the measuring head.

use

Such devices are used in the metrological testing of antenna technology of all kinds and in connection with electromagnetic environmental compatibility (EMC) as well as the harmlessness to health and acceptability for people, keyword: electrosmog .

Examples of such field strength or radiation measuring devices (see also: web links ) are the radiation measuring device EMR-300 from the former manufacturer Wandel & Goltermann (W&G) and the field measuring device NBM-550, which is sold by Narda .

See also

Web links

  • Datasheet of the field measuring device NBM-550 PDF; 1 MB (10 pages)
  • Brochure of the field measuring device NBM-550 PDF; 4.6 MB (9 pages)
  • Description of the radiation meter EMR-300 (4 pages)

Individual evidence

  1. ↑ Description at DARC.de, accessed on August 27, 2019.
  2. ↑ Data sheet at Narda-STS.com, accessed on August 28, 2019.