PAGE CONTENTS
Objectives
In response to the growing interest in broadcast services a new frequency band has been allocated in the 17/24 GHz band (17.3-17.7 downlink reverse to current DBS and uplink at 24.75-25.25 GHz). In order to achieve a sufficient power flux density on ground (e.g. for future BSS applications), transponder power levels exceeding 250W up to about 500W are required.
The current technology is limited in power handling and thermal constraints to about 250W for narrow bandwidth applications. This activity addresses the challenges for high power OMUX at Ka Band with narrow channel bandwidths.
The objective is to demonstrate extreme power handling at Ka Band using advanced RF, Mechanical, and Thermal design to build and test a proof of concept output multiplexer. Special consideration is to be given to all aspects of the high power design associated with self-heating, multipaction, corona breakdown and PIM.
Specific interest and attention will be given to critical components of the multiplexer which may pose a limitation to the power handling capability. By means of investigation and verification the manifold, irises and tuning elements will be carefully examined to ensure compliance and margin to the specifications outlined for the activity.
Challenges
The key issues presented by this project are overwhelmingly related to the power and thermal design. Loss and dissipation generally scale with frequency and channel bandwidth. This activity requires that the boundaries of both be extended. The thermal design is a significant driver of the complete OMUX design effort and tradeoffs will be anticipated at many points.
Plan
The project is divided into three elements.
Element 1 will investigate the OMUX technologies available to COMDEV to fulfil the requirements of the activity. This time will also be utilized to vet the chosen resonator and temperature compensation techniques.
Element 2 will focus on the filter specific design. This time will be spent investigating and designing the filter to withstand the significant RF and thermal demands of operating at 500W power in a fully contiguous condition.
The final phase will focus on the design verification. A multiplexer will be built and tested to verify the operation against the design.
All elements are planned to be complete in 24 months from kickoff. COMDEV have a dedicated R&D department and have allocated resources from that pool to the activity for the duration of the body of work.
Current Status
The activity is now complete. COMDEV have executed the contract as intended and the project objectives have been met and exceeded. COMDEV have developed a novel filter concept which exceeded the demands of the requirements. The final delivery demonstrated three variants of the filter concept on a single manifold underlining the flexibility and robustness of the design.
Companies
