How can I perform magnetic field test for MIL-STD RE101

Discussion and questions regarding the Radiated Emission and Conducted Emission modules of RadiMation.
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incognito
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How can I perform magnetic field test for MIL-STD RE101

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How can I perform radiated emission magnetic field tests as described in MIL-STD RE101?
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joro
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Re: How can I perform magnetic field tests for MIL-STD RE101

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The RE101 measurement as described by the MIL-STD, is just a normal emission measurement, with a specifically described loop sensor antenna.
For this Loop sensor antenna, the correction data is often well known, and provided by the manufacturer of the antenna. This correction data is expressed as dBpT above dBuV. The correction factor provided by the manufacturer thus only has to be added to the dBuV reading from the measurement receiver.

In RadiMation this can be configured by creating a correction file, which contains a 'Frequency' and a 'Correction' column. Then specify the frequencies and correction values in the correction file, where the correction values are expressed in dBpT/uV.
Once this Magnetic field antenna factor correction file is saved, selected it as the third correction file in the antenna device driver settings.
Magnetic field antenna factor selected in antenna configuration
Magnetic field antenna factor selected in antenna configuration
AHSystems-SAS-560-correction.png (22.59 KiB) Viewed 10996 times
In the Radiated Emission Multiband test, the correct testsite (containing the previously configured antenna) should be selected. And to indicate that a Magnetic Field test should be performed, it is also important to select 'Magnetic Field Antenna' for the location type.
Example TSF configuration for the MIL-STD RE101
Example TSF configuration for the MIL-STD RE101
RE101-TSF-Configuration.png (63.86 KiB) Viewed 10996 times
When this test is started, the emission measurement values will be shown in the result as dBpT.
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joro
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Re: How can I perform magnetic field test for MIL-STD RE101

Post by joro »

The same configuration as is described in this post can be used for the measurement of the magnetic field accoording to the CISPR 11 and the EN 55011.
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joro
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Re: How can I perform magnetic field test for MIL-STD RE101

Post by joro »

Some calibration certificates contain the magnetic field factor of the loop antenna as: K [dB(S/m)].
RadiMation however expects a correction file that is expressed in [dBpt/uV].
The conversion is: 'MagneticFieldFactor [dBpT/uV] = K [dB(S/m)] + 1.984'.
The value 1.984 is often simplified to be 2.0, but 1.984 is the more accurate value.

The relation between dBpT and A/m is: Magnetic Flux Density dBpT = dBuA/M + 1.984
In this equation, the constant 1.984 is derived as follows: The magnetic flux density, B in Teslas (T), is related to the magnetic field strength, H in A/m, by the permeability of the medium in Henry's per meter (H/m). For free space, the permeability is given as...

m0 = 4 * pi * 10E-7 H/m
B = m0 * H

Converting from T to pT and from A/m to uA/m, and taking the Log, the constant becomes...

240 - 120 + 20Log10[4 * pi * 10E-7] = 1.984 (to be exact: 1,9841972804419248955749215547977)

Also see: http://www.tf.uni-kiel.de/matwis/amat/e ... 4_1_1.html
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