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StatusOngoing
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Status date2011-11-22
| The objectives of the project are to develop wideband SSPAs for operation at L and S-band, and to also develop a new generation of MPA architecture offering operation at S-band to allow a wider bandwidth as anticipated for future applications. This will be accomplished by the development of an advanced wideband S-band SSPA, ONET and ancillary equipment, incorporated into an MPA. | 
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Also, a model of the system will be developed using ADS to enable analysis of the entire output network, which will allow optimum performance to be derived. This work will provide initially a theoretical model for the MPA, which will be updated by the inclusion of real measured data taken for the various components in the model.
The key issues to be addressed by this project are:
- Development of a wideband L-band SSPA,
- Development of a wideband S-band SSPA,
- Design and manufacture of a new small-footprint S-band ONET,
- Design and procurement of a GaAs MMIC chip-set that will provide improved gain and phase-tracking,
- Design and manufacture of MMC packaging to provide improved thermal properties of the SSPAs to aid their efficiency and integration into the MPA. Mass has been identified as a key issue for SSPAs.
At the conclusion of the project, new architectures of wideband L-band and S-band SSPAs will have been developed, built and tested to EQM level. Also, a new small-footprint S-band ONET will have been developed - this ONET will be incorporated into an MPA to assist theoretical modelling of the entire MPA. By operating at the higher S-band, a wider bandwidth capability will be available for expanded future mobile telecom applications.
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The architecture of the MPA system is shown in the figure at left. |
The prime items for development where critical performance of the MPA can be enhanced are the SSPAs and the ONET. A new folded-ONET was proposed, optimised for operation at S-band; scaling the new design back down to the currently popular L-band frequency band will be possible. A new SSPA will be developed, incorporating a new GaAs MMIC chip-set, new output power stage, improved control architecture, and new mechanical packaging incorporating a metal matrix composite (MMC) chassis for improved heat transfer and reduced mass. An ADS model will be constructed and populated with real measured data to enable the performance of the system to be evaluated when exercising the operational variables.
A Phase-A study identified a program of work to produce L and S-band SSPAs, using a new MMIC chip-set, metal matrix composite (MMC) chassis, a new S-band ONET, and the development of an MPA model. Phase-B kicked-off in November 2003.
his programme is now complete and has proved to have been extremely valuable for application to future mobile payload applications.
- An improved SSPA production process has demonstrated greater efficiency and productivity.
- New L/S band MMIC chip-sets for SSPA pre-amplifier and control have been produced.
click for larger image - An advanced Digital Control System has been demonstrated enabling reconfigurability of SSPA output power.
- An Astrium radiation hard cell library has been developed to implement the control circuitry as an ASIC and hardness to heavy ion irradiation has been demonstrated.
- L and S Band SSPAs have been designed with a reduced footprint, permitting closer integration to the spacecraft antenna.
- The concept for a 5W SSPA in HI-MMHT technology has been explored.
- UMS HB20S HBT process has been evaluated, and a flip chip assembly process has been outlined to alleviate thermal issues.
- A GaN SSPA with 60W output power capability has been demonstrated and heavy ion testing of the technology has provided confidence for further development.
click for larger image - A reduced footprint 8x8 ONET design has been manufactured and tested.
- Work has been carried out on improved MPA modelling and analysis. The analysis has been correlated with a fully integrated S Band MPA using commercial amplifiers.
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