The reverberation chamber´s unstirred field: A validation of the image theory interpretation

Synthetic aperture measurements of a reverberation chamber´s unstirred wireless channel are used to compare the observed power, time-of-arrival, and angle-of-arrival of unstirred multipath components to that predicted by ray/image theory for a rectangular cavity. An examination of the ray paths corresponding to erroneously predicted unstirred multipath components revealed that these ray paths intersect the reverberation chamber´s mode-stirring paddles, absorber blocks, and various other objects in the chamber. This inspired a simple image-blocking model for the reverberation chamber´s unstirred wireless channel, whereby contributions from ray paths intersecting the chamber´s mode-stirring paddles and absorbers are neglected. This model elucidates the unstirred wireless channel´s geometry-based multipath structure, justifies established best practices for reverberation chamber measurements, and enables the development of more effective techniques for mitigating the reverberation chamber´s unstirred field components.