Non-Redundant Spherical NF - FF Transformations Using Ellipsoidal Antenna Modeling: Experimental Assessments

Two non-redundant near-field-to-far-field (NF-FF) transformation techniques with spherical scanning, for antennas having a dimension very different from the other ones, are experiment ally tested in this paper. These techniques are based on the non-redundant sampling representations of the electromagnetic fields. They use a rotational ellipsoid to shape non-spherical antennas: a prolate ellipsoid for elongated antennas, and an oblate ellipsoid for the quasi-planar antennas. A two-dimensional optimal-sampling interpolation formula is employed to accurately recover the near-field data required by the classical spherical near-field-to-far-field transformation from the non-redundant near-field data. It is so possible to obtain a remarkable reduction in the number of the near-field samples to be acquired and, as a consequence, a remarkable reduction in the measurement time. Some experimental results, carried out at the Antenna Characterization Lab of the University of Salerno and assessing the effectiveness of the proposed techniques, are shown.