A Proposal to Improve the Standard on the Shielding Effectiveness Measurements of Materials and Gaskets in a Reverberation Chamber
In this paper, a reexamined estimate of the test fixture validation factor (TFVF) of fixtures for shielding effectiveness (SE) measurements in a reverberation chamber is shown. The fundamental conditions for the applicability of the model shown here are a large aperture between the chambers, whose transmission cross section is well approximated by the geometrical optics, and an isolation between the chambers greater than or equal to 10 dB, as specified in this paper. The model is applicable for both nonmarginal and marginal SE values; but, in the latter case, the requested isolation between the two chambers has to be met with no sample in the aperture. For nonmarginal SE values, the conditions requested for the applicability of the model are practically the same as those requested in the standard IEC 61000-4-21. The model is applicable to SE measurements of gaskets as well. The results show that the TFVF used in the standard procedure IEC 61000-4-21 has to be updated to achieve more accurate measurements of SE in light of the studies conducted on this topic. We give such an update in this study.