Validation of shielding effectiveness measurement method using nested reverberation chambers by comparison with aperture theory

In this paper we revisit existing methods for measuring the shielding effectiveness of material samples using nested reverberation chambers. These methods have the advantage of exposing the sample with a more realistic environment than other methods that are based on single plane wave excitation. That is, in the reverberation chamber the sample is exposed to fields with different incidence directions and polarizations resulting in that the average shielding effectiveness can be measured. We show by comparison with aperture theory that the measured shielding effectiveness corresponds to the theoretical value. We show also by measurements that a corrugation or choke on the periphery of an aperture can be used for increasing the shielding effectiveness for a narrow frequency range.