Pattern reconstruction from planar spiral near-field measurements @ UNISA Antenna Characterization Lab

The experimental assessment of a near field - far field (NF-FF) transformation technique with planar spiral scanning, which requires a minimum number of NF data, is provided. Such a technique, which allows a remarkable measurement time saving, relies on a nonredundant sampling representation of the voltage acquired by the measuring probe obtained by using the unified theory of spiral scannings for nonspherical antennas and modelling a quasi-planar antenna with an oblate ellipsoid. An optimal sampling interpolation formula is applied to efficiently retrieve the NF data required by the classical plane-rectangular NF-FF transformation from those collected along the spiral.