Design of a Ka-Band Sparse Array Antenna for Spaceborne SAR Applications

In this paper a novel sparse layout for the radiating aperture of a Ka-band spaceborne SAR is outlined. Starting from a set of typical requirements and the definition of a benchmark antenna, an approach to achieve sparsity (in terms of the number of active modules) is proposed, which reduces significantly the fill factor as compared to the benchmark array and at the same time maintains an acceptable level of complexity for manufacturing and testing. After an initial assessment of the radiation performance of the sparse layout, assuming isotropic radiators and ignoring mutual coupling, an actual design in slotted-waveguide technology is performed and an approach is devised to investigate the impact of mutual coupling on the radiation performance.