Cylindrical NF-FF transformation from NF data acquired on a non-classical sampling grid

An effective near-field-far-field transformation technique with cylindrical scanning using a nonclassical cylindrical grid is here proposed and experimentally validated. Such a grid is obtained by fixing the number of scanning generatrices according to the minimum cylinder rule and the number of near-field data on each of them according to the nonredundant sampling representation based on the spherical modelling of the antenna under test. A remarkable reduction of the number of near-field data with respect to the classical transformation thus results, since the distance between two consecutive sampling points on each generatrix increases when moving towards the periphery of the scanning cylinder. Moreover, the proposed technique allows the elimination of the characteristic ripple due to the discontinuity of the near field at the edges of the measurement cylinder.