Effects of multipath in a spherical near-field system

Results are presented which indicate a substantially reduced susceptibility to multipath interference for an SNFMS (spherical near-field measurement system) as compared to a conventional antenna measurement system. Specific mechanisms that contribute to this reduced susceptibility are range-length-related defocusing, elemental area kernel and off-centre geometry-related filtering. Polar and equatorial measurement geometries have totally different properties in relation to susceptibility to multipath. In the polar case, the multipath interference appears in the predicted far-field response as a perturbation spread over a much wider solid angle