Articulated Boom for Deployable Antenna Reflector
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Solution Overview
Problem
Single offset reflector antennas in space missions suffer from poor cross-polar properties due to asymmetry, limiting their applicability, and require complex designs like Gregorian geometries that increase mass and accommodation space, while long focal lengths are needed for improved scanning performance.
Innovation Solution
A compact, articulated boom with hingedly-connected joints and a 'dog-leg' design allows for the deployment of large diameter antenna reflectors with long focal lengths, reducing cross-polar issues and eliminating the need for complex subreflector designs, featuring a support arm that extends from a stowed position to a deployed position using stepper motors or spring-operated hinges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If single offset reflector antennas are used, then the design is simple, but cross-polar properties deteriorate due to asymmetry
Solution Approach 1:
The patent applies asymmetry by using a single offset reflector geometry that deliberately exploits asymmetric positioning to achieve the desired radiation pattern while managing cross-polar effects through careful geometric optimization rather than symmetric cancellation
2Object-generated harmful factors
If Gregorian-type reflector geometries are used, then cross-polar properties improve, but mass and accommodation space increase
Solution Approach 1:
The patent extracts the subreflector component from the Gregorian configuration, using only the main offset reflector with optimized geometry to achieve acceptable cross-polar performance without the additional mass and complexity of the subreflector system
Solution Approach 2:
The patent changes the geometric parameters of the offset reflector, specifically optimizing the focal length to diameter ratio and offset angles to achieve improved cross-polar performance and scanning characteristics without requiring a Gregorian subreflector
3Object-generated harmful factors
If Gregorian-type reflector geometries are used, then cross-polar properties improve, but accommodation space increases
Solution Approach 1:
The patent removes the subreflector assembly from the configuration, reducing the accommodation space required while maintaining acceptable cross-polar performance through optimized main reflector geometry
Solution Approach 2:
The patent optimizes the focal length to diameter ratio parameter, using longer focal lengths to improve scanning performance and cross-polar characteristics while managing the space requirements through efficient structural design
4Productivity
If long focal lengths are used, then scanning performance improves, but the boom structure becomes more complex
Solution Approach 1:
The patent segments the boom structure into multiple articulated sections with hingedly-connected joints, allowing the long focal length configuration to achieve improved scanning performance while managing structural complexity through modular design
Solution Approach 2:
The patent implements a deployable articulated boom that can transition between stowed and deployed configurations, enabling long focal length operation for improved scanning performance while reducing complexity and space requirements during non-operational phases
Data Source
AI summary
An articulated boom comprises a support arm with a plurality of hingedly-connected joints. The arm is adapted and arranged to carry an antenna reflector so that in use, the reflector can move between a first stowed position in which the reflector is in folded condition and a second deployed position in which the reflector is in deployed condition. A spacecraft incorporates into one or more of its sides a plurality of such articulated booms. The support arms of the booms can be advantageously positioned at the circumference of the associated reflectors when in a stowed position, so as to allow the reflectors to be neatly stacked together within a space defined by the launch vehicle fairing.