Abstract-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 modestirring 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.