Description
Priority 2: Priority 2 activities will only be initiated on the explicit request of at least one delegation.
Objective:
Design and develop an innovative dual polarisation transmit/receive feed for a large dimension focal array with a focus on mass reduction without a radio-frequency performance penalty.
Targeted Improvements:
Mass and volume reduction of 30%.
Description:
Large array fed reflectors have traditionally supported only a single polarisation while operating in both transmit and receive simultaneously. There is now growing interest in expanding this envelope to support dual polarisation and transmit and receive operation simultaneously. While it is possible to solve this problem by suitable element selection, and doubling the number of diplexers, this significantly increases the mass of the feed array.
Developments in the technology and concepts in both the antenna feeds and filters, present an opportunity to develop innovative solutions, which individually or in combination could significantly reduce the mass impact of operating dual polarisation and transmit/receive simultaneously. For example the use of a self-diplexed radiating element that is able to isolate on its own the transmit and receive bands and would allow to remove or to reduce the size of the diplexer whose design is driven by the isolation requirement.
Solutions for self-diplexed radiating elements utilising stacked patch antennas have already been implemented with success on navigation satellites. Another promising antenna solution making use of electronic band gap (EBG) structure and proximity coupled elements allow to reach an isolation of about 60 dB.
Filters that are capable of operating on both orthogonal polarisations simultaneously would allow the signal to be diplexed into receive and transmit signals before being split by polarisation. The target development will be at L, S or C-Band. While large array fed reflectors are viewed as the key market, the technology may also be applicable to DRAs.
The activity will consist of:
- Establishment of a set of performance requirements for the feed element/diplexer suitable for use with a large array fed reflector.
- Technology Survey for:
- Self-diplexing radiating element
- Dual polarisation diplexer.
- Candidate solution development
- Trade-off and selection of the most promising feed architecture and identification of key breadboards to be manufactured and tested.
- Manufacture and testing of breadboards
- The development roadmap