Experimental validation of the SVD based approach to compensate the positioning errors in a nonredundant spherical NF-FF transformation

An efficient near-field - far-field (NF-FF) transformation with spherical scanning for long antennas, requiring a minimum number of irregularly spaced data, is experimentally validated in this work. It is based on a nonredundant sampling representation of the voltage measured by the probe, obtained by assuming the antenna under test as enclosed in a prolate ellipsoid, a modelling particularly suitable for electrically long antennas. The singular value decomposition method is employed to recover the NF data at the points fixed by the sampling representation from the acquired nonuniformly distributed ones, which are assumed to lie on irregularly spaced parallels. Once the uniform NF data have been reconstructed, those needed by the classical spherical NF-FF transformation are efficiently evaluated by an optimal sampling interpolation formula. Some experimental results, performed at the Antenna Characterization Lab of the University of Salerno and assessing the effectiveness of such a technique for compensating known positioning errors, are shown.

[1]  Bradley K. Alpert,et al.  Near-field antenna measurements using nonideal measurement locations , 1997 .

[2]  Flaminio Ferrara,et al.  Effective Antenna Modellings for NF-FF Transformations with Spherical Scanning Using the Minimum Number of Data , 2011 .

[3]  Flemming Larsen.  Probe correction of spherical near-field measurements , 1977 .

[4]  R. Wittmann,et al.  The receiving antenna as a linear differential operator: Application to spherical near-field scanning , 1985 .

[5]  J. E. Hansen,et al.  Spherical near-field scanning at the Technical University of Denmark , 1988 .

[6]  Flaminio Ferrara,et al.  Experimental validation of the NF–FF transformation with cylindrical scan from nonuniformly distributed data , 2011 .

[7]  Ovidio Mario Bucci,et al.  Interpolation of electromagnetic radiated fields over a plane by nonuniform samples , 1993 .

[8]  Paul F Wacker,et al.  Non-planar near field measurements: Spherical scanning , 1975 .

[9]  Flaminio Ferrara,et al.  Two Techniques for Compensating the Probe Positioning Errors in the Spherical NF–FF Transformation for Elongated Antennas , 2011 .

[10]  Flaminio Ferrara,et al.  Far-Field Reconstruction from Nonuniform Plane-Polar Data: A SVD-Based Approach , 2003 .

[11]  Flaminio Ferrara,et al.  Experimental Testing of Nonredundant Near-Field to Far-Field Transformations with Spherical Scanning Using Flexible Modellings for Nonvolumetric Antennas , 2013 .

[12]  Clive Parini,et al.  Spherical near-field antenna measurements , 2014, Theory and Practice of Modern Antenna Range Measurements, 2nd Expanded Edition, Volume 2.

[13]  Thorkild B. Hansen.  Numerical Investigation of the System-Matrix Method for Higher-Order Probe Correction in Spherical Near-Field Antenna Measurements , 2012 .

[14]  Flaminio Ferrara,et al.  A singular value decomposition based approach for far-field reconstruction from irregularly spaced planar wide-mesh scanning data , 2007 .

[15]  C. H. Schmidt,et al.  Adaptive Sampling in Spherical and Cylindrical Near-Field Antenna Measurements , 2013, IEEE Antennas and Propagation Magazine.

[16]  Flaminio Ferrara,et al.  Non-Redundant Spherical NF - FF Transformations Using Ellipsoidal Antenna Modeling: Experimental Assessments [Measurements Corner] , 2013, IEEE Antennas and Propagation Magazine.

[17]  Ovidio Mario Bucci,et al.  Data Reduction in the Nf-Ff Transformation Technique With Spherical Scanning , 2001 .

[18]  Sergey Pivnenko,et al.  Theory and Practice of the FFT/Matrix Inversion Technique for Probe-Corrected Spherical Near-Field Antenna Measurements With High-Order Probes , 2010, IEEE Transactions on Antennas and Propagation.

[19]  Ovidio Mario Bucci,et al.  Electromagnetic fields interpolation from nonuniform samples over spherical and cylindrical surfaces , 1994 .

[20]  Ovidio Mario Bucci,et al.  Application of Nonredundant Sampling Representations of Electromagnetic Fields to NF-FF Transformation Techniques , 2012 .

[21]  Vladimir Rokhlin,et al.  Fast Fourier Transforms for Nonequispaced Data , 1993, SIAM J. Sci. Comput..

[22]  Thorkild B. Hansen,et al.  Spherical Near-Field Scanning With Higher-Order Probes , 2011, IEEE Transactions on Antennas and Propagation.

[23]  O. Bucci,et al.  Representation of electromagnetic fields over arbitrary surfaces by a finite and nonredundant number of samples , 1998 .

[24]  Flaminio Ferrara,et al.  On the Compensation of Probe Positioning Errors When Using a Nonredundant Cylindrical Nf-Ff Transformation , 2010 .

[25]  Flaminio Ferrara,et al.  NF–FF transformation with cylindrical scanning from nonuniformly distributed data , 2003 .

[26]  J. Hansen.  Spherical near-field antenna measurements , 1988 .

[27]  G. Franceschetti,et al.  On the spatial bandwidth of scattered fields , 1987 .

[28]  R.C. Wittmann,et al.  Near-field, spherical-scanning antenna measurements with nonideal probe locations , 2004, IEEE Transactions on Antennas and Propagation.