M10.9 CONVEX BOUNDARY ARRAYS FOR COHERENT

The beam pattern of an aperture of sensor elements determines the quality of the image of farfield sources produced by it. Resolution is limited by the physical size of the aperture in linear beamforming, and sidelobe characteristics are determined by the aperture weighting function or aperture apodization. elements the largest two-dimensional physical apertures are formed if elements are distributed only around their boundaries. This, however, results in beam patterns with rather high sidelobes. I n this paper we extend results we have developed recently to show that in general, for any convex boundary aperture in a plane, it is possible to synthesize any beam pattern which is obtainable from a filled aperture with the same boundary. We review briefly specific results f or elliptical and rectangular boundaries, and then establish a general synthesis theorem which provides the b asis of the two-dimensional pattern synthesis scheme. This is applicable for both incoherent and coherent imaging, the latter implemented using a transmit-receive scheme. For a given number of