Our client asked our assistance in developing a ground-based mobile system required to meet some very challenging technical specifications but do it at a low cost using Commercial Off The Shelf (COTS) components. Our highly experienced Antennas, Arrays, & Optics team was able to rapidly eliminate solutions that were a poor cost/performance fit and focus in on a solution that reduced costs below budget and shortened development time by months.
The client’s task was to design and analyze a reflector antenna system using a varying number of feed elements in an array. The overall requirement was to achieve the best peak gain performance while using a COTS (Commercial Off The Shelf) parabolic reflector antenna to achieve the budget limitations of the program. The candidate Configurations considered were: Single axially symmetric antenna, Cassegrain antenna, Single offset, dual offset, and a confocal dual offset.
The symmetric antennas were eliminated due to severe aperture blockage, especially due to the sub-reflector in a Cassegrain configuration. Both the single offset and the offset dual reflector ideally requires a single feed. An array feed is still possible but would not be very efficient. Ultimately, the confocal offset reflector system, with a COTS parabolic main reflector and a parabolic sub-reflector, was chosen as the optimum configuration. In addition to being the best system using a planar array configuration, this configuration allows the possibility of using a larger array with a different sub-reflector, without changing the main reflector. It therefore allows the greatest desired growth scalability while requiring the least change to antenna components.
The initial exercise was to investigate the availability of commercially available inexpensive parabolic reflectors. Once options were identified, the next step was to arrive at an optimum parabolic sub-reflector size and shape to be used with the array. As a part of the trade study, the size of the sub-reflector was also investigated.
The design and analysis were performed using the commercially available software GRASP and yielded an optimum confocal antenna system. This system makes use of a far cheaper COTS reflector than originally budgeted with flexibility for simple sub-reflector and feed array changes for maximum growth flexibility, at the best cost. The client was very happy with the design, achieved performance and clear cost savings of the components and design.
Using experience CREAN Antennas, Arrays, and Optics team members eliminated numerous costly design/test/redesign iterations and accelerated their schedule with an immediate solution with the analysis simulations needed to have confidence in the solution.
CREAN. For when it does take a rocket scientist.