Nonredundant spherical near-field to far-field transformation for an offset mounted long antenna

Abstract

An effective probe compensated near-field - far-field (NF-FF) transformation with spherical scanning for an offset mounted long antenna, requiring a number of NF data that is minimum and equal to that needed in a centred configuration, is developed in this work, by applying the nonredundant sampling representations of the electromagnetic field and modelling the antenna under test (AUT) by a prolate ellipsoid. The interest for it arises from the fact that, for practical constraints, it could be not possible a centred mounting of the AUT on the scanning sphere centre and, for an offset mounting, the number of NF data required by the classical spherical NF-FF transformation can considerably grow due to the increase of the radius of the minimum sphere containing the AUT and centred on the scanning sphere centre.