Nonredundant spherical spiral scanning for offset mounted long antennas

An efficient nonredundant near-field – far-field (NF-FF) transformation with spherical spiral scan suitable for offset mounted elongated antennas is here developed. It allows a remarkable measurement time saving, since the NF data are acquired via a spiral scan and their number is minimum and practically the same of that required in a centred mounting. This result is got by properly exploiting the unified theory of spiral scans for nonspherical antennas and modelling them by a cylinder with two hemispherical caps