Performance Evaluation of Oscillating Wall Stirrer in Reverberation Chamber Using Correlation Matrix Method and Modes Within $Q$-Bandwidth

To evaluate the performance of oscillating wall stirrer (OWS) in reverberation chamber (RC), the number of independent stirrer positions, and field distributions (in lessmoded, undermoded, and overmoded frequency regimes) are discussed in detail in this work. For the estimation of independent stirrer positions, correlation matrix method (CMM), i.e., threshold-dependent correlation matrix defined by Pearson correlation coefficient, is used to determine the number of independent stirrer positions, where experimental comparative analysis between autocorrelation coefficient in IEC 61000-4-21 and CMM is presented, and the corresponding results provide a reasonable explanation for the overestimation of independent stirrer positions. For the field distributions, parameter
$M$
in Bessel
$K$
distribution, related to the number of excited modes within
$Q$
-bandwidth, is adopted to assess the quasiwall-like behavior of OWS in lessmoded, undermoded, and overmoded RCs, respectively, and the results show that OWS can distribute the field energy that was not sufficiently stirred with a higher probability (
$>$
50%) at undermoded frequencies.