Spatial domain indirect holographic technique for antenna near-field phaseless measurements

A spatial domain formulation of an indirect holographic technique, useful for antenna near-fieldphase retrieval, is presented in this paper. The proposed approach is based on the adoption of three syntheticreference signals, giving three sets of amplitude-only near-field data. These are directly processed in thespatial domain to accurately retrieve the near-field phase, from which the antenna radiation features can besubsequently computed. Despite the standard indirect holographic approach, no data processing is requiredin the spectral (Fourier transform) domain, thus completely avoiding the problem of spectrum overlappingwhich limits the accuracy of standard method. The effectiveness of the proposed technique is demonstratedby a numerical test on a linear dipole array, as well as by experimental results on a ridged-horn antenna.