Confocal antenna system
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Solution Overview
Problem
Dual parabolic confocal antenna systems suffer from poor aperture efficiency and high main reflector spillover, leading to scattering and electromagnetic interference issues in satellite applications, due to the inherent tradeoff between these factors.
Innovation Solution
A confocal antenna system with a shaped sub-reflector having regions with different curvatures optimized for various scan directions, reducing main reflector spillover and improving energy focusing on the feed array, thereby enhancing antenna efficiency and reducing scattering and EMI.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If dual parabolic confocal reflector configuration is used to achieve signal magnification, then gain is improved, but aperture efficiency deteriorates and reflector spillover increases
Solution Approach 1:
The sub-reflector is divided into multiple regions, each with a different curvature optimized for specific scan directions. This local differentiation of curvature allows each region to efficiently direct energy to its corresponding feed array elements, improving overall aperture efficiency while maintaining the confocal magnification configuration
Solution Approach 2:
The patent employs dynamic shaping of the sub-reflector where the curvature varies continuously across different regions to accommodate scanned beam directions. This dynamic adaptation of surface geometry enables the system to maintain optimal performance across multiple scan angles rather than being fixed for a single direction
2Power
If dual parabolic confocal reflector configuration is used to achieve signal magnification, then gain is improved, but reflector spillover increases causing scattering and EMI
Solution Approach 1:
By assigning different curvatures to different regions of the sub-reflector, each region is optimized to direct reflected energy precisely to its intended feed array elements. This prevents energy from spilling over the main reflector edges, eliminating the scattering and EMI problems associated with traditional dual parabolic configurations
Solution Approach 2:
The patent transforms the potential harmful spillover energy into useful directed energy by carefully designing the regional curvatures. The shaped sub-reflector regions that would otherwise cause spillover are instead configured to redirect this energy onto the feed array, converting a harmful effect into a beneficial one
3Loss of energy
If magnification is reduced to improve aperture efficiency, then spillover decreases, but gain is reduced or feed size must be increased
Solution Approach 1:
The patent changes the curvature parameter of the sub-reflector across different regions, optimizing each region's shape to achieve both high aperture efficiency and maintained gain. By varying the curvature rather than using a uniform parabolic shape, the system achieves improved energy efficiency without sacrificing the magnification and gain benefits of the confocal configuration
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 shaped sub-reflector design increases antenna efficiency, reduces energy loss, and improves beam performance by ensuring better energy centering on the feed array across all scan angles, minimizing scattering and EMI issues.
Implementation Method 1
the sub-reflector is configured to direct electromagnetic energy rays to the main reflector
Implementation Method 2
confocal antennas are used in communication satellites to magnify the image of a feed array
Data Source
AI summary
A reflector for an antenna includes a first shaped region, wherein a curvature of the first shaped region is defined by a corresponding scan angle, and a second shaped region, wherein a curvature of the second shaped region is based on a corresponding scan angle. The curvature of the first shaped region is different than the curvature of the second shaped region.