Sub-reflector Panel Adjustment for Aperture Phase Correction
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Solution Overview
Problem
In large-diameter antenna devices, self-weight deformation of the main reflector causes aberration and non-uniform phase distribution at the aperture surface, leading to reduced aperture efficiency, and existing adjustment methods are costly and inefficient, especially when dealing with elevation angles and the installation of sub-reflector modules.
Innovation Solution
An antenna device with a sub-reflector having drive mechanisms for its panels, a primary emitter to receive radio waves, and a phase calculator to determine optimal sub-reflector panel positions based on changes in received electric-field strength, minimizing phase distribution on the main reflector's aperture surface without adjusting the main reflector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If drive mechanisms are installed on each panel of the main reflector to adjust mirror surface position, then manufacturing precision of the aperture surface is improved, but device complexity and cost increase significantly
Solution Approach 1:
The patent introduces a sub-reflector as an intermediary component between the main reflector and the primary emitter. Instead of directly adjusting each panel of the main reflector, the sub-reflector with its drive mechanisms serves as a mediator to compensate for aperture surface errors. This reduces the complexity from having drive mechanisms on every main reflector panel to having them only on the sub-reflector panels.
Solution Approach 2:
The sub-reflector is divided into multiple sub-reflector panels, each with its own drive mechanism. This segmentation allows for localized adjustment of the sub-reflector surface to compensate for main reflector aperture errors, achieving high precision adjustment with fewer total drive mechanisms compared to adjusting every main reflector panel individually.
2Measurement precision
If a plane mirror larger than the main reflector is installed to measure and adjust mirror surface, then measurement precision is improved, but ease of operation deteriorates due to installation difficulty
Solution Approach 1:
Instead of placing a large plane mirror in front of the main reflector to measure its surface (as in conventional methods), the patent inverts the approach by placing the measuring and adjusting means (sub-reflector with drive mechanisms) behind the main reflector. This reversal makes the system easier to install and operate while maintaining measurement precision.
Solution Approach 2:
The sub-reflector and its drive mechanisms are nested within the structure behind the main reflector, utilizing the available space in the antenna feed system. This nesting approach eliminates the need for external large-plane mirror installations, improving ease of operation while maintaining measurement capabilities.
3Ease of operation
If the entire sub-reflector is moved to the main focal position of a deformed main reflector, then position adjustment is simplified, but manufacturing precision of the aperture surface deteriorates due to remaining aberrations
Solution Approach 1:
The patent makes the sub-reflector surface dynamic by equipping each sub-reflector panel with drive mechanisms that can independently adjust the panel positions. This allows the sub-reflector surface shape to be dynamically changed to compensate for main reflector deformations, achieving high aperture surface precision while maintaining operational simplicity.
Solution Approach 2:
The patent changes the parameters of the sub-reflector panel positions through drive mechanisms, allowing precise control over the sub-reflector surface shape. By adjusting these parameters, the system can compensate for main reflector deformations and achieve uniform phase distribution across the aperture surface.
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
This approach allows for accurate and cost-effective adjustment of the sub-reflector, compensating for aberrations caused by main reflector deformation, thereby improving aperture efficiency without altering the main reflector's position.
Implementation Method 1
a sub-reflector (12) having a reflecting surface facing a reflecting surface of the main reflector (11)
Implementation Method 2
a phase calculator (171) to calculate, based on a change in received electric-field strength of a radio wave received by the primary emitter (13) during driving of the sub-reflector panel drive mechanisms (122_n), relative phases of element electric-field vectors corresponding to the sub-reflector panels (121_n)
Data Source
AI summary
An antenna device includes a main reflector (11), a sub-reflector (12) including sub-reflector panels and having a reflecting surface facing a reflecting surface of the main reflector, and a primary emitter (13) to receive a radio wave reflected by the sub-reflector (12). Each of sub-reflector panel drive mechanisms coupled to the sub-reflector panels is finely driven. A phase calculator (171) calculates a relative phase of an element electric-field vector corresponding to each of the sub-reflector panels based on a change in received electric-field strength of the radio wave received by the primary emitter (13) during driving of the sub-reflector panel drive mechanisms, and determines positions of the sub-reflector panels at which a phase distribution on an aperture surface of the main reflector (11) is minimized.