On the Low-Frequency Optimization of Reverberation Chambers

An original method allowing to define a particular frequency called “quasi-ideal reverberation chamber (RC) minimum frequency” is presented. This frequency corresponds to the frequency where an RC is considered as working in a “quasi-ideal regime.” According to the definition of an ideal RC, the method is based on the assessment 1) of the electromagnetic (EM) field distributions obtained in the working volume (in comparison with the distributions obtained in the ideal model defined by Hill [D. A. Hill, “Plane wave integral representation for fields in reverberation chambers,” IEEE Trans. Electromagn. Compat., vol. 40, no. 3, pp. 209--217, Aug. 1998.]) and 2) of the number of uncorrelated samples obtained over one mode stirrer revolution. The method is considered as helpful in order to optimize the functioning of an RC at low frequencies for broadband EM compatibility immunity and emission tests. Indeed, it is shown from experimental and numerical results that the insertion of an optimal loading in the chamber allows to decrease the frequency where the chamber works quasi-ideally. The influence of complexifying the mode stirrer geometry is also discussed.