Introduction [Singular-value optimization in plane-polar near-field antenna characterization]

We develop a near-field/far-field (NFFF) transformation approach for characterizing planar aperture antennas from planepolar scanning data. The radial and azimuthal field-sampling spacings are chosen to provide the minimum number of nearfield samples, optimizing the singular-value dynamics of the relevant linear operator connecting unknowns and data. A numerical and experimental analysis is provided, showing how the approach is capable of significantly reducing both the number of required samples and the number of measurement rings, as compared to the advanced sampling techniques available in the literature.