Description
Past activities on modulated metasurface antennas have shown that a proper layout of sub-wavelength features on antenna surfaces is very effective in controlling the antenna pattern of a flat disk-shaped antenna fed from a single point. In particular sectorial-beam isoflux-shaped patterns with good cross-polarisation appeared to be feasible achieving a EOC directivity between 20 dBi and 30 dBi.
The activity has therefore been focusing on the development of specific solutions for data down-link antennas for LEO missions, with minimum complexity and as small a foot-print as possible offering the possibility for azimuth and elevation scanning at Ka-band. Different antenna and scanning configurations where addressed, resulting in the design, manufacturing and test of a demonstrator. The design relies on a 250 mm flat-disk modulated metasurface, fed by a circular waveguide and radiating a fan-shaped beam. Full coverage of the visible area on ground is achieved by an in-plane azimuth rotation driven by a small motor housed in a cylindrical compartment below the disk hosting also the feeding network. The assembly is about 50 mm thick.
