Numerical and experimental investigation of unstirred frequencies in reverberation chambers

The paper analyzes the occurrence of unstirred frequencies in a reverberation chamber. Both experimental and numerical field data are checked applying the Kolmogorov-Smirnov test. The presence of these frequencies is unavoidable, even eliminating evident causes. Their value changes introducing small perturbations of the antenna relative position or stirrer starting points in the chamber. In the case of simulated field, based on plane wave expansion, similar unstirred frequencies are still present and their variation are related to the change of the field observation points or of the plane wave set randomly generated.