Compensation of 3-D Position Errors in a Nonredundant NF/FF Transformation with Spherical Scan

In this work, a novel two-stages approach, which allows the compensation of known 3-D mispositioning errors corrupting the data in a non-redundant (NR) spherical near-field / far-field (NF/FF) transformation for quasi-flat antennas, is developed. In the first stage (the so-called NR correction), an adequate phase factor is removed from the gathered voltage samples to compensate for the phase errors brought on by the deviations from the measurement sphere. In the sub-sequent stage, an iterative scheme is used to recover the NF samples at their exact positions from those got in the previous stage. Finally, the NF data required to execute the standard spherical NF/FF transformation are got from the retrieved correctly positioned samples via an optimal sampling interpolation formula. Accuracy and efficacy of the approach are numerically validated.