An antenna pattern synthesis technique for spaceborne SAR performance optimization

An antenna pattern design technique for spaceborne synthetic aperture radars (SARs) that optimizes the signal-to-disturbance ratio is presented. It takes into account the ground reflectivity (relative to the transmitted frequency) and the viewing geometry (altitude and off-nadir angle). The technique makes use of the theory of adaptive arrays and takes advantage of a priori knowledge of the ambiguous echo power as a function of the geometry and average ground reflectivity. The optimized antenna weighting turns out to be complex, and asymmetrical patterns are generally obtained for a spaceborne SAR. The technique allows the achievement of better performance compared to the current design values, especially at large off-nadir angles