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Objectives
The objective of this project is to design, build and test a Q/V-band Feed System EQM (Engineering Qualification Model) so that this technology is qualified for flight use on future GEO VHTS systems.
This project draws on the successful development of a Feed System EM (Engineering Model) through a previous ARTES 5.2 programme.
The Feed System EM is shown in Figure 1.
This product’s primary use is for gateway feed chains in multi-spot beam antennas on board geostationary VHTS systems. The usage of the Q/V-band on the gateway link frees up spectrum on the Ka-band user links. With the exception of the mission specific filters and feed horns, these feeds are generic and can be adapted for different missions. An example Q/V-band gateway coverage is shown in Figure 2.
Challenges
The Q/V-band Feed System has to be a slim-line design:
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compatible with up to 7 feeds and 30mm spacing between feeds with suitable mechanical interfaces in a feed cluster.
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covering the complete Q Tx, Q Rx and V Rx bands
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operating in dual circular polarisation over all frequency bands
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capable of handling maximum RF power levels without risk of multipaction
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exhibiting low PIM performance over temperature
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compatible with the envisaged thermal and vibration environment at component level as well as Feed System level
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achieving required RF performance across multiple builds
System Architecture
A generic wideband feed architecture has been selected for this EQM feed development. This comprises of a wideband feed horn, wide band polariser, wide band OMT, and a pair of triplexers to accommodate the most challenging filter frequency plan, as shown in Figure 3.
Plan
Phase 1: KO to PDR
Preliminary design phase includes activities to validate key technologies used in EQM. PIM test requirements are defined.
Phase 2: PDR to CDR
Detailed design and analyses performed. Plans defined for PIM tests.
Phase 3: CDR to TRR
EQM components are manufactured. Components and sub-assemblies undergo RF health checks before full Feed System is assembled and RF tested.
Phase 4: Final Review
Feed System EQM is subjected to qualification testing (thermal cycling, vibration, power handling and PIM tests). Test reports are included in FR documentation.
Current Status
Phase 4 completed.
Flight qualification of the Q/V-band Feed System is complete.
