Array current distributions to generate flat-topped beams

The generation of shaped beam antenna patterns is of considerable importance in satellite and radar systems. Orchard´s (1985) synthesis procedure can be applied to equispaced linear arrays that will generate shaped patterns like the cosec/sup 2//spl theta//spl times/cos/spl theta/ pattern (useful in ground-mapping radars and aircraft beacons), and flat-topped patterns (useful in satellite broadcast systems). Elliott and Stern (1985) synthesized planar arrays with real current distributions to obtain flat-topped beams with elliptical contour. Linear program synthesis and transformation techniques have also been applied to generate two-dimensional shaped-beam patterns. We describe real-valued linear array current distributions, derived from the Legendre polynomials, that can generate flat topped beams of controllable width.