The objective of the Ka-Band Multibeam Antenna Development Study program is to advance MDA's existing Ka-band multibeam antenna designs and enable the development of new technologies that will have significant cost, performance and functional advantages over past technologies.
This requires work in four areas: antenna analysis tools, feed cluster design, feedchain design and feedchain assembly methods.
In the Study phase of the program, the focus will be on developing breadboard designs and overall concepts that will be further refined in the follow-on phase of the program.
The key issues for the feedchains are:
- RF performance over both Transmit and Receive frequency bands, notably return loss and axial ratio,
- Low mass,
- Very compact envelope,
- Low cost as the typical system requires 50 to 90 feedchains,
- Fast, efficient, reliable assembly techniques.
The key issues for the Cluster design are:
- Design concepts that are easily applied to different geometries of feedchain layout,
- Overall part count,
- Accessibility and ease of assembly,
- Low mass,
- Low overall thermally induced distortion,
- Thermal control.
The key issues for the antenna calculation tools are:
- Developing a technically rigorous method of performing the C/I calculation,
- Fast run time.
The market for a next generation of Ka-Band multibeam systems is currently expanding at a rapid pace. As an independent second tier suppler of antennas, MDA can team with various satellite prime contractors to offer multibeam solutions for all such systems provided our technology is sufficiently advanced and our cost is competitive. This program provides MDA with the opportunity to develop a suitable solution to meet this market.
The antenna analysis tools will be created to implement a technically rigorous method of performing the complex Carrier over Interference (C/I) calculations for a multibeam system, automatically define the optimal cells, and assess the performance with complex, varying pointing error requirements.
The Cluster design effort will develop overall structural concepts for the design of feed clusters comprising 20 or more feedchains. The design will address assembly issues, structural interfaces, waveguide layout and thermal control.
The current generation of multibeam antennas requires feedchains that perform both Receive and Transmit functions. In addition, some feedchains must work in both polarizations. While this type of feedchain is not new, being able to package the feedchain in the very small envelope to fit within the cluster while retaining excellent RF performance is a significant challenge that will be addressed in this program.
A further challenge with the feedchains is to develop techniques for cost effective and quick assembly and testing. This is especially critical given the extreme tolerances required at Ka-Band frequencies for proper RF performance. This will be addressed in this program through innovative piecepart machining techniques and advanced assembly and test fixtures.
The overall program will culminate in the qualification of feedchains and the testing of a PFM antenna. The Study phase will focus on the foundations of this activity, such as developing the RF design of the feedchains and creating the breadboard drawings, performing trade-offs to decide on the overall cluster structural concept and developing the antenna calculation tools required to analyze this type of complex antenna system.
The Study phase of the program has been completed and the Final Review has been successfully held.
The antenna calculation tools have been developed and are being used extensively on current programs. The baseline design concepts for the Cluster structure have been developed and are about to be applied to the detailed design. The RF designs of the feedchains are complete and the breadboard drawings have been created. Designs for assembly fixtures have been developed.