This paper proposes a method for estimating the excitation of array antennas by backward‐transforming phaseless field data into the very near‐field. The very near‐fields are reconstructed at the antenna aperture using the Tikhonov source current reconstruction method (SRM). Two field amplitudes in different planes recover very near‐field data from phaseless fields. The excitation estimation technique relies on the localised nature of very near‐field currents around the antenna. Through spatial filtering of the reconstructed equivalent currents, the current distribution of each individual element is isolated. The excitation of each array element is then determined by analysing its current distribution over a separate surface mesh. Excitation estimations of two different array antennas with measurement and simulation results have been carried out to validate the proposed method. The relative amplitude errors of the excitation estimation with simulation data are 7.5% and 3.9% for using equivalent electric and magnetic current, respectively. In the measurement scenario, which includes the errors of manufacturing and testing, the maximum relative amplitude error is about 12% and the maximum phase recovery deviation is about 9°.

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