Steerable Satellite Antenna Assembly with Fixed Feed
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Solution Overview
Problem
Steerable satellite antenna assemblies require high gain, low mass, and high reliability, while also needing to avoid the 'keyhole effect' and achieve a more compact geometry to accommodate the growth and demand for bandwidth in satellite constellations operating in medium earth orbit (MEO) and low earth orbit (LEO), where traditional designs are limited by size, weight, and the need for wider beam scanning ranges.
Innovation Solution
A compact steerable antenna assembly is designed without a subreflector, featuring a fixed antenna feed, a rotatable frame with a parabolic main reflector, and a splash plate, utilizing L-shaped and flat configurations for the antenna feed and reflectors, respectively, with rotational actuators for azimuthal and elevational positioning, allowing for a more compact and cost-effective design that maintains performance across a wide scanning range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional steerable antenna assembly with subreflector is used, then the antenna can achieve high gain and reliable operation, but the assembly becomes larger and heavier, increasing satellite mass and cost
Solution Approach 1:
The patent removes the subreflector component from the traditional antenna assembly, extracting only the essential elements (main reflector, feed, and splash plate) needed to achieve the desired functionality. This extraction reduces the number of parts and overall mass while maintaining high gain and reliable operation through the simplified reflector-splash plate configuration
Solution Approach 2:
The patent applies local quality by optimizing the specific geometry and positioning of the main reflector and splash plate to compensate for the removed subreflector. The splash plate is positioned and shaped to provide the necessary signal redirection and focusing locally, replacing the function previously distributed across multiple components
2Reliability
If a traditional antenna assembly with multiple components is used, then the antenna can maintain stable performance, but the assembly becomes more complex and costly
Solution Approach 1:
The patent extracts and removes the subreflector component from the antenna assembly, reducing the total number of parts from four (feed, subreflector, main reflector, support structure) to three (feed, main reflector, splash plate). This simplification reduces assembly complexity and manufacturing cost while maintaining performance stability through optimized geometry of the remaining components
Solution Approach 2:
The patent merges the functions of the subreflector and splash plate into a single integrated splash plate structure that performs both signal redirection and focusing. This consolidation reduces the number of separate components and interfaces, simplifying the overall device while maintaining the necessary signal path control for stable performance
3Volume of moving object
If a compact antenna geometry is implemented, then the satellite size and weight are reduced, but the scanning range and beam coverage may be limited
Solution Approach 1:
The patent employs dimensional optimization by carefully positioning the splash plate at a specific distance and angle relative to the main reflector, creating an optimized three-dimensional configuration. This spatial arrangement allows the compact assembly to achieve wide scanning ranges by maximizing the angular coverage provided by the reflector-splash plate geometry without increasing overall volume
Solution Approach 2:
The patent applies parameter changes by optimizing the geometric parameters of the main reflector (parabolic shape, focal length, aperture diameter) and splash plate (position, orientation, surface area) to achieve a compact form factor that simultaneously provides wide beam scanning capability. The specific parameter values are selected to balance compactness with scanning range requirements for MEO and LEO orbits
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 solution results in a reduced satellite size and weight, lower costs due to fewer parts, and stable antenna performance over a wide scan range, with net antenna gains varying between 28.5 to 36.6 dB across different frequencies, ensuring reliable communication without sacrificing wide scan angle performance.
Implementation Method 1
a main reflector, which is fixed to the frame and has a parabolic shape
Implementation Method 2
a splash plate, which is carried by the frame in spaced apart relation from the main reflector and has a flat shape
Data Source
AI summary
An antenna assembly to be carried by a satellite includes an antenna feed configured to extend outwardly from the satellite, and a frame rotatably carried by the antenna feed and is rotatable about a first rotation axis. A main reflector is carried by the frame and is aligned with the antenna feed. A splash plate is carried by the frame in spaced apart relation from the main reflector and is rotatable about a second rotation axis.