Probe compensated near-field to far-field transformation with helicoidal scanning for elongated antennas

An innovative near-field -far-field transformation technique with helicoidal scanning is proposed in this work. It makes use of an ellipsoidal modelling of the source, instead of the previously adopted spherical one. Such a modelling, tailored for elongated antennas, allows one to consider measurement cylinders with a diameter smaller than the source height, thus reducing the error related to the truncation of the scanning surface. Moreover, it contains the spherical modelling as particular case and lowers significantly the number of required data when dealing with elongated antennas. Some numerical tests, assessing the accuracy of the technique and its stability with respect to random errors affecting the data, are reported.