An Effective Procedure to Correct Known Three-Dimensional Probe Position Errors Affecting a Non-Redundant Cylindrical Near-Field to Far-Field Transformation

This work shows an efficient two steps procedure to correct known 3-D probe positioning errors which occur in the non-redundant (NR) near-field to far-field (NF-FF) transformations with cylindrical scanning. As a first step, a phase correction, in the following called as cylindrical wave correction, is applied to achieve the correction of the positioning errors due to the deviations of the collected NF samples from the nominal measurement cylinder. After that, an iterative technique will be employed to perform the restoring of the NF samples at the points imposed by the NR sampling representation from those got at the previous step and corrupted by 2-D positioning errors. Once the two steps procedure has been successfully applied, the data required to execute the traditional cylindrical NF-FF transformation are accurately reconstructed by using a 2-D optimal sampling interpolation (OSI) expansion. It is important to point out that, to develop the NR sampling representation and the related OSI expansion, it is mandatory to adopt an efficient modeling of the antenna under test. Such a modeling has been obtained by considering the antenna as enclosed in a rounded cylinder, namely a cylinder terminated by two half spheres. Some numerical simulations will be shown to fully validate the effectiveness of the developed procedure in compensating for even serious 3-D positioning errors.