Offset Reflector Antenna with Deployable Hoop Assembly
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Solution Overview
Problem
Conventional antenna systems, such as hoop column reflector (HCR) types, face challenges in providing a low-cost, easily modifiable, and efficient offset-fed reflector system that can concentrate RF energy effectively while maintaining a compact design for various missions.
Innovation Solution
A compact deployable reflector system featuring a hoop assembly with link members and a collapsible mesh reflector surface, secured by cords to an extendible boom, allowing for passive expansion and offset positioning of the mast relative to the hoop, enabling efficient RF energy concentration in a desired pattern.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the mast is centered inside the hoop assembly, then the structure is simpler and more symmetric, but blockage and sidelobes increase reducing RF efficiency
Solution Approach 1:
The patent applies asymmetry by offsetting the mast position relative to the hoop assembly center. The mast is positioned at a distance of 0.05λ to 0.15λ from the center, creating an asymmetric configuration that reduces blockage and sidelobes, thereby improving RF energy efficiency and reducing energy loss.
2Stability of the object's composition
If the hoop assembly is made rigid and fixed, then the reflector shape is more stable, but the compaction ratio decreases and deployability is reduced
Solution Approach 1:
The hoop assembly is segmented into multiple link members (typically 8-16 links) connected by hinges, allowing the structure to be divided into collapsible sections that can be compacted for deployment while maintaining structural integrity and shape stability when deployed.
Solution Approach 2:
The hoop assembly transitions from a static fixed structure to a dynamic deployable structure. The link members with hinges enable the assembly to collapse into a compact configuration for storage/transport and expand into a stable deployed configuration for operation, achieving both compactness and shape stability.
3Power
If the reflector surface is made large to improve RF energy concentration, then the gain increases, but the system size and weight increase
Solution Approach 1:
The patent uses a thin mesh reflector surface made of flexible material that can be tensioned into the desired parabolic or offset-fed shape. This thin film approach achieves the required RF energy concentration and gain while minimizing weight compared to traditional solid reflector surfaces.
Solution Approach 2:
The reflector system employs a nested deployment mechanism where the hoop assembly with link members can collapse into a compact nested configuration for launch/transport, then expand to the full operational size for RF energy concentration, effectively reducing the transported volume while maintaining the large operational aperture.
4Loss of energy
If conventional HCR antenna systems are used, then the compaction ratio is high, but they lack offset-fed configuration reducing efficiency and increasing blockage
Solution Approach 1:
The patent creates a universal offset-fed reflector system that can be adapted to multiple mission requirements. The modular hoop assembly with adjustable link members and the offset mast configuration provide a versatile platform that can serve different RF applications while maintaining high efficiency and reduced blockage characteristics.
Data Source
Figure 1A~1B
Figure 1C
Figure 1D
AI summary
A reflector system includes a hoop assembly formed of a plurality of link members extending between a plurality of hinge bodies. The link members have an expanded configuration wherein the link members define a circumferential hoop having a central hoop axis. A collapsible mesh reflector surface is secured to the hoop such that when the hoop assembly is in the expanded configuration, the reflector surface is expanded to a shape that is intended to concentrate RF energy. A mast assembly includes an extendible boom aligned along a central boom axis. The hoop assembly is secured by a plurality of cords relative to the boom such that when the hoop is expanded, a central hoop axis is laterally offset a predetermined distance from the central boom axis.