An Approach to Compensate 3-D Probe Positioning Errors Affecting the Non-Redundant Cylindrical Near-Field Measurements

This communication provides an effective two-steps strategy to compensate for known 3-D probe positioning errors occurring in the non-redundant (NR) cylindrical near-to-far-field (NTFF) transformations. As first step, a phase correction, here denoted as cylindrical wave correction, is employed to perform the correction of the positioning errors relevant to the deviations of the measured NF samples from the nominal scanning cylinder. Then, an iterative procedure will be applied to retrieve the NF samples at the points specified by the adopted sampling representation from those obtained at the previous step and affected by 2-D positioning errors. Finally, after properly reconstructing the correctly distributed cylindrical samples, the data necessary to apply the classical cylindrical NTFF transformation can be restored in accurate way by employing a 2-D optimal sampling interpolation (OSI) formula. It should be noticed as, to derive the NR sampling representation, as well as the OSI scheme, it is necessary to provide a proper modeling of the antenna under test. This modeling has been got by shaping the source with a prolate spheroid. Numerical tests will show the capability of the procedure to compensate these 3-D positioning errors.