PAGE CONTENTS
Objectives
The objective of this project is the design of a full in-flight reconfigurable Ku-band high power broadcast antenna with flexible power allocation, working on multiple-regional beams and continental beams coverage, with dual-polarization capability, to cope with changes in user demand over the satellite lifetime. Moreover the demonstration of the proposed concept is requested and implemented by means of the design, manufacturing and test of a critical part of the selected baseline architecture.
Challenges
The main challenges tackled in this activity are the following:
- Design of an innovative full in-flight reconfigurable antenna system, minimizing operative risks using consolidated technology for space applications (i.e. antenna reflectors).
- Minimization of the number of controls, in order to reduce the antenna BFN and HPA section complexity.
- Control of antenna grating lobe contributions, considering feed array design technique based on sparse/aperiodic feed array configurations.
- Maximization of the system DC power efficiency, with the HPAs amplitude unbalance controlled in the RF antenna optimization loop.
- RF and mechanical design of the single horn of the feed cluster as antenna critical breadboarding, working on the entire operative band at both linear polarizations, with a very high radiation efficiency and a very compact envelope and mass.
- RF and mechanical design of the Confocal antenna Demonstrator, composed by an 1×42 amplitude/phase re-configurable low power BFN, the complete Feed Cluster of 42 rectangular feed horns with OMTs and the Confocal antenna sub-reflector.
- RF test with the designed and manufactured critical breadboarding and antenna Demonstrator.
Plan
The overall activities of this project have been split in two phases (Phase 1 and Phase 2), plus a CCN (CCN3).
The Phase 1, Phase 2 and CCN3 of the project have been carried out with the following milestones, with the related major achievements:
Phase1:
- KO (Kick-Off)
- BDR (Definition of Mission Scenario, Selection of baseline Antenna configuration and Definition of baseline Antenna Requirements)
- PDR (Antenna preliminary design and analysis, Sub-Systems identification and development plan, Demonstrator definition)
Phase 2:
- KO (Kick-Off)
- CDR (Critical Breadboarding design, manufacture and test, Antenna detailed RF analysis, Demonstrator detailed design)
- TRB (Demonstrator manufacture and RF test)
- FR (Final Review)
CCN3:
- KO (Kick-Off)
- PM (Additional RF test on KuRBA Demonstrator, further detailed analysis for different HPA load unbalances, grating lobes and scanning capability, comparison of the designed Confocal antenna with an existing satellite antenna solution)
- FR (Final Review)
Current Status
All the activities foreseen for the Phase 1, the Phase 2 and the CCN3 of the contract have been carried out.
The RF measurement results achieved with the KuRBA Demonstrator are really very good as compared with the simulations. This very good agreement between analyses and measurements have been confirmed by also all the additional RF tests carried out in the frame of the CCN3 of the contract.
The effectiveness of the Confocal antenna approach, associated with sparse/aperiodic array feeding system, seems to be definitively demonstrated for reconfigurable regional/continental coverage missions in Ku-band.
