Far-field reconstruction from planar spiral data using an effective modelling of the antenna

A new near-field - far-field transformation technique with planar spiral scanning is here proposed. It makes use of a very flexible source modelling, which fits very well a lot of actual antennas. By employing such a modelling, instead of the spherical one, it is possible to significantly reduce the error related to the truncation of the scanning zone, since the near-field data can be now acquired on a spiral lying on a measurement plane at a distance smaller than one half the source maximum size. Some numerical tests, assessing the accuracy of the technique and its stability with respect to random errors affecting the data, are reported.