Segmented Hoop Antenna for Compact Stowage
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Solution Overview
Problem
Conventional hoop-type reflector antennas face challenges in achieving compact stowage length due to the required out-of-plane thickness and bending stiffness, making it difficult to design a compact and lightweight structure that maintains a desired parabolic shape when stowed.
Innovation Solution
A deployable reflector system featuring a hoop assembly with a plurality of link elements that expand to form a circumferential hoop, including X-members with pivot members and tension elements, allowing the reflector surface to be secured and expanded to concentrate RF energy in a desired pattern, while maintaining a compact stowed volume and reduced weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a conventional hoop structure with sufficient bending stiffness is used, then the hoop can maintain its shape and prevent warping, but the stowed length along the hoop center axis becomes elongated (equal to 2H where H is the deployed thickness)
Solution Approach 1:
The hoop is divided into multiple discrete elements (first hoop elements and second hoop elements) that are coupled together. This segmentation allows the hoop to achieve the necessary stiffness through the arrangement and coupling of elements rather than requiring each individual element to be thick and rigid, thereby reducing the stowed length while maintaining shape stability.
Solution Approach 2:
The first and second hoop elements are nested or coupled in a configuration where they interlock or support each other. This nesting arrangement provides mutual structural support, enabling the hoop to maintain its shape with thinner elements, thus reducing the overall stowed length along the central axis.
2Manufacturing precision
If the hoop is made thicker to achieve desired parabolic shape, then the parabolic surface accuracy is improved, but the stowed volume and weight increase
Solution Approach 1:
The hoop is segmented into multiple thin elements that work together to achieve the required structural performance. This segmentation allows the use of thinner materials that can be stowed in a more compact volume while maintaining the ability to form an accurate parabolic shape when deployed.
Solution Approach 2:
The hoop elements utilize composite construction where multiple materials or structures are combined to achieve high stiffness-to-weight ratio. This allows the hoop to maintain accurate parabolic shape with reduced thickness, thereby reducing stowed volume and weight.
3Length of moving object
If a radial rib reflector design is used, then the structure is collapsible for compact stowage, but the stowed height is approximately equal to the reflector's radius
Solution Approach 1:
The reflector structure is divided into radial rib elements that can be independently collapsed and stowed. This segmentation enables the reflector to be compacted to a height approximately equal to half the reflector's radius, improving upon conventional radial rib designs while maintaining structural integrity.
4Length of moving object
If a folding rib reflector is used, then the stowed height is reduced to approximately half of radial rib design, but the stowed diameter becomes larger
Solution Approach 1:
The hoop elements are arranged and coupled in a three-dimensional configuration that optimizes both stowed height and diameter. By utilizing spatial arrangement in multiple dimensions rather than simple linear folding, the structure achieves compact dimensions in both height and diameter when stowed.
Data Source
AI summary
Reflector antenna system includes a hoop assembly comprising a plurality of link elements which are rigid and extend between a plurality of hinge members, the hoop assembly expandable between a collapsed condition where the link elements are substantially parallel to one another and an expanded condition wherein the link elements define a circumferential hoop around a central axis. The hoop assembly defines a plurality of N rectangular sides, each comprised of an X-member including first and a second link element in a crossed configuration. A plurality of tension elements extend around the periphery of the side and apply tension between opposing ends of the first and second link elements in directions aligned with the top, bottom and two opposing sides.