Laboratory Tests on a Near-Field to Far-Field Transformation Technique from Non-redundant Bi-Polar Data

An experimental verification of a fast and accurate technique, which allows the evaluation of the antenna radiation pattern from a non-redundant, i.e. minimum, number of near-field measurements acquired via a bi-polar scan, is provided in this paper. This probe compensated near-field to far-field (NFTFF) transformation exploits a non-redundant sampling representation of the voltage acquired by the probe, achieved by shaping the antenna with a double bowl, a very flexible model particularly tailored to antennas characterized by a quasi-planar geometry. The input NF data necessary for executing the standard plane-rectangular NFTFF transformation are efficiently recovered from the acquired non-redundant bi-polar ones by applying a 2-D optimal sampling interpolation formula, so that a remarkable measurement time saving is attained. Some results of laboratory proofs performed at the Antenna Characterization Lab of the University of Salerno are reported to demonstrate the accuracy and the practical effectiveness of the presented NFTFF transformation technique