Optimized spherical near-field antenna measurements

An optimized Near-Field/Far-Field (NFFF) transformation technique for the characterization of aperture antennas in spherical geometry is here presented. In particular, the approach introduced in [5,6] for the planar geometry is extended to the spherical one. The NFFF transformation is formulated as a linear inverse problem, and the number and the locations of the sampling points over the measurement sphere are chosen as the ones optimizing the singular value dynamics of the linear system. The performance of the method is evaluated also by a comparison with existing approaches considered, up to now, as the most convenient ones.