Improvement of coupling corrected difference beams in small phased arrays

The corrupting effects of mutual coupling between radiating elements of small phased arrays means that conventional aperture weighting schemes (Taylor, Chebyshev etc.) cannot be applied to small phased array antennas to form low sidelobe sum and difference beams. The corrupting effects of mutual coupling can be removed by the determination of an inverted coupling matrix. This description of the couplings is not perfect. Thr imperfect coupling matrix description means the synthesised beams are degraded. particularly difference beams where a deep look direction null is an important characteristic of the beam. The results of applying an adaptive algorithm to the coupling corrected array weight vector in order to enhance difference beam nulls is presented.