Deployable Reflectarray Antenna Using S-Shaped Springs
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Solution Overview
Problem
Current deployable RF antennas for small satellites, such as CubeSats, face challenges in achieving large aperture sizes while maintaining compact stowage and efficient RF performance, particularly in limited launch volumes.
Innovation Solution
A large-area deployable reflectarray antenna design using collapsible S-shaped springs and quartz-epoxy composite strips, which can be folded and wrapped for compact storage, providing a 1.5 m×1.5 m aperture with a robust and lightweight structure that maintains RF performance and planarity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a large aperture antenna is deployed, then RF gain and beam pattern performance are improved, but the stowage volume and device complexity increase
Solution Approach 1:
The reflectarray surface is divided into multiple discrete elements (dipoles and ground plane segments) that can be independently folded and stowed. Each element is separated by collapsible S-shaped springs, allowing the large aperture to be segmented into compact units for storage while maintaining the overall array configuration for operation.
Solution Approach 2:
The antenna structure employs a nested folding mechanism where the reflectarray surface is folded into a compact configuration that fits within the limited CubeSat volume. The S-shaped springs collapse to allow adjacent facesheets to fold against each other, creating a nested stowage configuration that minimizes volume while preserving the large aperture geometry for deployment.
2Stability of the object's composition
If the antenna structure is made rigid to maintain planarity, then structural integrity is improved, but the stowage compactness and ease of deployment decrease
Solution Approach 1:
The antenna structure transitions from a static rigid design to a dynamic deployable system. The S-shaped springs provide controlled flexibility that allows the structure to change configuration between stowed and deployed states. During deployment, the springs expand to provide mechanical support and separate adjacent facesheets, automatically achieving and maintaining planarity without requiring rigid structural elements.
Solution Approach 2:
The structural parameters of the antenna are changed through the deployment mechanism. The S-shaped springs change their geometric configuration from a collapsed state (for stowage) to an expanded state (for deployment), which alters the separation and positioning of facesheets. This parameter change enables the structure to achieve planarity dynamically rather than being inherently rigid.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design allows for a compact stowage of a 1.5 m×1.5 m aperture in a 4U CubeSat volume with minimal impact on RF gain and beam pattern, achieving 39.6 dB of gain or better at 8.4 GHz, and maintains structural integrity and planarity during deployment and stowage.
Implementation Method 1
a plurality of collapsible S-shaped springs attached to the first facesheet and to the second facesheet, and being configured to: collapse during folding of the reflectarray, thus allowing adjacent facesheet to fold against each other in the folded configuration, and provide mechanical support for the reflectarray in the deployed configuration, separating adjacent facesheet
Data Source
AI summary
A deployable reflectarray has a plurality of strips arranged in quadrants forming the reflectarray. The copper ground plane and the copper dipoles are supported by facesheets made of epoxy reinforced by quartz fibers. The copper ground plane is separated from the copper dipoles by S-shaped springs made of epoxy reinforced by quartz fibers, which allow folding and deployment of the reflectarray.