Description
*On Delegation Request (formerly called Priority 2)
Objective: The objective of the activity is to develop a Ka-band compact multiple-feed-per-beam feed system in waveguide technology incorporating some dual-polarisation beams for serving both user and feeder links.
Targeted Improvements: 30% to 50% length reduction in comparison to today' s state of the art multiple-feed-per-beam feed system implemented in waveguide technology. Elimination of the dedicated gateway reflector antenna in multiple-feed-per-beam antenna systems, with associated savings in mass, volume and cost.
Description: Multi-feed-per-beam systems are of great interest for broadbandsatellite missions as they enable the generation of the full multibeam coverage with only two reflector antennas. Possible future use of this technology includes multibeam broadband missions, also on smaller platforms, secondary payloads, or missions with a smaller beam size (i.e. larger reflector apertures) as currently contemplated in Very-High-Throughput satellite systems. A significant advancement of today's multi-feed-per-beam feed systems could be achieved by developing a dual-polarisation capability at beam level, hence enabling the use of the same user link antenna for the gateway link (each gateway is typically operated in dual-polarisation),i.e. eliminating the need for a separate gateway antenna. Today's state of the art multi-feed-per-beam feed systems also suffer from accommodation challenges on the spacecraft. In particular, the length of the feed system is critical. This is a consequence of theincreasing bandwidth requirement, the large number of splitting layers required and the use of separate beam forming networks (BFN)for each polarisation.
In this activity a concept shall be developed that enables the sharing of the same multi-feed-per-beam antenna for the user and feeder links by making use of a beam forming network operating in dual-polarisation at beam level. Such a feed system does not exist today, and applications have been identified. Novel sub-components (e.g. combined E-plane/H-plane or even 3D couplers) that can cope with dual polarisation will need to be developed. Significant modelling and design challenges will need to be tackled to design a full antenna feed array based on such unconventional components. At Ka-band, standard waveguide technology can offer attractive solutions, as low insertion losses can be achieved and sophisticated RF design tool are available. New overlapping schemes and size reduction of the feed system, as well as RF performance improvement, shall be investigated. A detailed antenna design shall be performed and a scaled engineering model of a compact Ka-band dual-polarisation multiple-feed-per-beam feed system shall be designed, manufactured and tested experimentally to evaluate the developed concept. The scaled engineering model shall include all critical components of the dual-polarisation beam forming network from the travelling wave tube amplifier outputs up to the antenna feed ports.
*On Delegation Request (formerly called Priority 2) activities will only be initiated on the explicit request of at least one National Delegation.