The objective is to design an antenna system capable of generating multiple hopped or switched antenna beams from a combined transmit/receive aperture, or from one aperture operating in transmit mode and one in receive mode, and to verify its critical functions.
Targeted Improvements: Decrease the number of antenna apertures and the associated cost by a factor of greater than two when compared to today's conventional solution.
Description Broadband antennas capable of generating multiple, contiguous beams within a frequency/polarisation reuse scheme fall into two categories, each with different maturity and flexibility: single feed per beam antennas, requiring at least three antenna apertures, and multiple feed per beam antennas, requiring only two antenna apertures at the expense of greater feed system complexity.
In beam hopping or beam switching applications some of the technical challenges associated with the simultaneous generation of contiguous beams are removed. This enables the introduction of innovative antenna architectures having lower complexity and offering improved performance, with the possibility of generating all beams from a single antenna aperture. Being able to generate dedicated pencil beams to focus on areas with high traffic demand, either as a stand-alone mission or to complement an European or other regional coverage, is considered of great commercial interest, as it provides traffic flexibility andconnectivity at a limited cost when compared to alternative antenna solutions.
Among others, an antenna architecture based on overlapping feeds, thanks to a parasitic structure placed in front of the feed apertures, shows promise. However, in such configurations, when all beams are generated simultaneously, complex, critical and bulky high order filters are needed on each feed to prevent coupling among beam ports operating in the same polarisation and at nearby frequencies. One possible improvement is to replace the filters by switches, which connect individual feeds to either a beam port or a short circuit. Other technical solutions avoiding the useof switches are also possible. Considering dual polarisation feeds, adjacent beams can be created and radiate over the full frequency band, enabling full flexibility in traffic allocation. Moreover, full frequency spectrum and polarisation can be allocated to a given beam.
In this activity the technical requirements for a beam hopping antenna will be consolidated and promising antenna concepts investigated, leading to the design and development of a single reflector beam hopping antenna for high throughput satellites. A partial, scaled engineering model of a feed system incorporating all critical functions shall be designed, developed, manufactured and experimentally verified. The performance of the overall antenna will be evaluated by analysis, taking into account the measurementresults for the feed system.