Correlation-Based Uncertainty in Loaded Reverberation Chambers
Maria G. Becker, Michael R. Frey, Sarah B. Streett, Catherine A. Remley, Robert D. Horansky, Damir Senic
When reverberation chambers are loaded to increase the coherence bandwidth for modulated-signal measurements, a secondary effect is decreased spatial uniformity. We show that an appropriate choice of stirring sequence, consisting of a combination of mode-stirring mechanisms such as paddle and antenna platform stirring, can mitigate the potential for increased uncertainty. We develop a new mode-stirring-sample correlation model for uncertainty due to stirring sequence. In a comparison with an empirical uncertainty analysis, the model is found to have agreement to within 2.5%. Our analysis is demonstrated for four loading cases in each of three reverberation chambers. The model is used to determine an optimal stirring sequence for a given chamber setup directly from correlations associated with each stirring mechanism. The model can also be understood in terms of the entropy of a measurement, and it is shown that maximizing the entropy corresponds to a minimized uncertainty. The method presented here not only provides insight into sources of uncertainty, but also allows users to determine an optimal mode-stirring sequence with minimized uncertainty for a given chamber setup.
IEEE Transactions on Electromagnetic Compatibility