Rectangular Reflector Antenna Subreflector Beam Shaping
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Solution Overview
Problem
Conventional reflector antenna devices with rectangular aperture shapes suffer from reduced radiation levels at peripheral corners and increased spillover losses, limiting the degree of freedom in reflector shaping without improving efficiency.
Innovation Solution
A reflector antenna device featuring a main reflector with a rectangular aperture and a subreflector with a mirror surface having asperities that converts a circularly shaped beam from a primary radiator into a rectangular shape, matching the main reflector's aperture shape, thereby enhancing the degree of freedom in reflector shaping without efficiency reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a main reflector with a rectangular aperture shape is used to maximize aperture area utilization under satellite mounting constraints, then the degree of freedom for reflector shaping is improved, but the radiation level at peripheral corners decreases and spillover loss increases
Solution Approach 1:
A subreflector is introduced as an intermediary component between the primary radiator and the main reflector. The subreflector has a mirror surface with asperities that convert the circular beam shape from the primary radiator into a rectangular shape matching the main reflector's aperture, thereby mediating the energy distribution to reduce spillover loss while maintaining rectangular aperture utilization
Solution Approach 2:
The mirror surface of the subreflector is given non-uniform local quality through the formation of asperities. These localized surface variations selectively modify the beam shape in different regions, converting the circular amplitude distribution to rectangular while controlling energy distribution to prevent spillover
2Adaptability or versatility
If the radiation level at peripheral parts of a rectangular main reflector is increased to improve beam shaping freedom, then reflector shaping flexibility is enhanced, but spillover loss from the center portion increases and efficiency degrades
Solution Approach 1:
The subreflector acts as a mediator that transforms the beam shape before it reaches the main reflector. By converting the circular beam to rectangular shape at the subreflector stage, the main reflector can operate at full efficiency without spillover losses, while still achieving the desired rectangular beam output
Solution Approach 2:
The amplitude distribution parameter of the beam is changed from circular to rectangular shape through the subreflector's asperities. This parameter transformation allows the system to achieve rectangular beam shaping freedom while maintaining optimal energy utilization and antenna efficiency
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 improves the gain and isolation performance by up to 0.2dB and 1dB respectively, allowing for more effective shaping of the reflector antenna beam without compromising efficiency.
Implementation Method 1
a subreflector which has a mirror surface on which asperities are formed, to convert the shape of the beam radiated by the primary radiator from a circular shape to a rectangular shape similar to the aperture shape of the main reflector, and which reflects the beam and radiates the beam having the amplitude distribution with the rectangular shape onto the main reflector
Data Source
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AI summary
A reflector antenna device is configured to include a main reflector 1 that has a rectangular aperture shape 2, and a primary radiator 3 that radiates a beam having a rectangular shape similar to the aperture shape 2 of the main reflector 1 onto the main reflector 1. As the primary radiator 3, a multimode horn antenna, an active phased array antenna, or the like can be used. As a result, the degree of freedom of reflector shaping can be improved without causing reduction in efficiency.