Best fit approach for amplitude and phase near-field array measurements

The design of an active electronically scanned array antenna (AESA), in which amplitude and Gil are controlled by MMIC circuits requires a precise and convenient measurement bench, in order to adjust the field radiated by each source. To be effective, this bench must have a precision better than about 1° in phase and 0.2 dB in amplitude. The principle of the measure rests on a planar near-field-scanning and processing of measured data in which the exact (measured) positions of the sources are used instead of being reconstructed as well as the complex amplitudes of the fields, like in others methods. This method can take into account diffractive points like ends or obstacles and quantify their share in the overall radiation. It was implemented and used to adjust small arrays. Comparisons were made between theoretical and measured amplitudes and were very positive. Results on the overall precision are given in this paper