Laboratory tests on a near-field — Far-field transformation with spherical scan using a very flexible antenna modelling

An effective near-field - far-field (NF-FF) transformation with spherical scanning for quasi-planar antennas is experimentally validated in this work. It is based on a nonredundant sampling representations of the electromagnetic fields using a flexible source modelling formed by two circular “bowls” with the same aperture but different lateral bends. Such a modelling, suitable to fit very well a lot of quasi-planar antennas, allows a remarkable reduction of the number of data to be acquired and, as a consequence, of the measurement time. An optimal sampling interpolation algorithm is employed to efficiently recover the NF data needed by a probe compensated NF-FF transformation with spherical scanning. The effectiveness of the approach is experimentally assessed at the UNISA Antenna Characterization Lab by comparing the FF patterns reconstructed from the nonredundant NF measurements with those obtained from the NF data directly measured on the classical spherical grid.