A novel hybrid approach for far-field characterization from near-field amplitude-only measurements on arbitrary scanning surfaces

Comparison of non-convex cost functionals for the consideration of phase differences in phaseless near-field far-field transformations of measured antenna fields

“…A natural choice for an additional row inside the norm of the cost functional is to use the magnitude of a linear combination of two already existing measurements. The goal value β N +1 for this linear combination magnitude can be obtained from additional measurements with special probes as in Costanzo et al (2005) or can easily be computed from known magnitudes and phase differences analogous to Eq. (7).…”

“…It remains unclear, how such measurements can be obtained in a NF antenna measurement scenario. Interferometric methods have been used to obtain phase differences from magnitude only measure-ments in Costanzo et al (2005). There, the measured phase differences have been set up along a chain from one element to the other, thus being very inflexible in the measurement setup.…”

“…Phase differences can be obtained from magnitude only measurements of certain linear combinations as in Costanzo et al (2005) or by the assumption that a global reference phase will be stable for at least two successive measurements. Finding a global minimum to a cost functional involving both, magnitudes and phase differences, is equivalent to determining the near field up to a global phase shift.…”

Advanced Numerical Techniques for Near-Field Antenna Measurements

“…Generally speaking, two classes of phaseless methods can be distinguished, the one based on a functional relationship within a proper set of amplitude-only data (Pierri et al, 1999), the other adopting interferometric techniques (Bennet et al, 1976). In some recent works (Costanzo et al, 2001;Costanzo and Di Massa, 2002;Costanzo et al, 2005;2008), a novel hybrid procedure has been proposed which combines all the best features of the two kinds of phaseless methods. A basically interferometric approach is adopted, but avoiding the use of a reference antenna as required in standard interferometry.…”

Phaseless spherical near-field antenna measurements for low and medium gain antennas

“…Amplitude measurements are less critical in terms of measurement equipment and accuracy compared to phase measurements, even for high frequencies. This is why phaseless measurement techniques (Yaccarino and RahmatSamii, 1999;Pierri et al, 1999;Las-Heras and Sarkar, 2002;Costanzo et al, 2005;Soldovieri et al, 2005;Schejball et al, 2008) have obtained considerable interest in research. Costly vector network analysers are no longer required for phase measurements and also phaseless techniques show some superior robustness for some classes of errors (Razavi and Rahmat-Samii, 2008).…”