Interleaved Isophoric Sparse Arrays for the Radiation of Steerable and Switchable Beams in Satellite Communications

We address the synthesis of isophoric sparse ring arrays for full-Earth coverage from Geostationary Earth Orbit (GEO) satellites by means of steerable beams, switchable between two different widths. In particular, we pursue the desired beam zooming/shrinking through two interleaved sparse arrays deployed over the available circular aperture. To this aim, we propose two different antenna architectures. In one case, the two beams are radiated by two separate interleaved arrays; in the other case, the two beams are instead radiated by two interleaved arrays that share a common part of their layouts. Both the proposed architectures allow us to exploit a synthesis procedure that calculates the two interleaved arrays separately, through the cascade of two steps, both implemented with a (computationally) very efficient deterministic density-tapering approach. The proposed strategy allows to obtain isophoric sparse layouts, satisfying the required design constraints with a significant reduction of the control points with respect to the solution achievable exploiting noninterleaved isophoric sparse arrays.