Wideband validation of a phase retrieval process applied to infrared planar near-field measurements

The framework of our work is the application of a fast method to estimate the radiation pattern of an antenna from the measurement of the electric-field magnitude in the near-field region using infrared (IR) camera. IR acquisition techniques allows quasirealtime measurements of the magnitude of the electrical field on planar surfaces in near-field conditions. However the antennas radiation patterns can only be estimated from near-field electrical magnitude and phase measurements. Consequently a classical plane to plane iterative phase retrieval process has been developed and tested with respect to a large number of configuration parameters such as to find an optimal configuration on a wide frequency range [0.5-20 GHz]. In order to achieve and validate such a study, some comparisons have been performed on data obtained either by numerical simulation or classical near-field technique based upon radio-frequency (RF) probe scanning on simple horn antennas. Among all the studied parameters we will focus onto the influence of the dynamic range of the measurements on the reconstructed radiation patterns and on validations from experimental results.