Multifocal Reflector Antenna Wide-Angle Scanning
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Solution Overview
Problem
Current phased array antennas and reflector-based antennas are impractical for wide electronic beam scanning due to limited scan angles, high cost, and complex design, making them unsuitable for commercial applications such as satellite and terrestrial communications, and radar systems.
Innovation Solution
A multifocal reflector antenna system with at least four segments of paraboloids defining multiple focal points, allowing for electronic scanning over a wide angular range with fewer elements, enhancing scan capability and reducing complexity and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a phased array antenna is used to provide electronically scanned beams, then beam scanning speed and low physical profile are improved, but the number of antenna elements increases to hundreds or thousands, increasing complexity and cost
Solution Approach 1:
The reflector surface is divided into multiple segments (at least four segments of paraboloids), each with different curvatures defining different focal points. This segmentation allows the system to achieve wide electronic scanning with a reduced number of phased array elements by distributing the focusing function across multiple reflector segments.
Solution Approach 2:
A multifocal reflector is introduced as an intermediary between the phased array feed and the radiation field. The reflector with multiple focal points acts as a mediator that transforms the limited scanning capability of a conventional single-focus system into wide-angle electronic scanning, reducing the need for numerous array elements.
2Measurement precision
If the number of phased array elements is increased to improve directivity, then directivity is improved, but complexity and cost increase
Solution Approach 1:
The reflector is segmented into multiple paraboloid sections, each contributing to focusing energy in different directions. This allows the system to achieve high directivity across a wide scanning range without proportionally increasing the number of phased array elements, as each segment enhances the effective aperture utilization.
Solution Approach 2:
The curvature parameters of the reflector segments are optimized to define multiple focal points. By changing the geometric parameters of the reflector surface, the system achieves variable directivity patterns and wide scanning capability with a fixed, reduced number of array elements.
3Measurement precision
If a conventional reflector antenna is used to increase directivity without increasing phased array elements, then directivity is improved, but electronic scanning capability is limited to about ±10 beamwidth
Solution Approach 1:
The reflector surface is divided into multiple segments with different curvatures, each segment focusing energy at different angles. This segmentation enables electronic scanning over a wide angular range (at least ±10 beamwidth) while maintaining high directivity, overcoming the limitation of conventional single-focus reflectors.
Solution Approach 2:
The multifocal reflector performs multiple functions simultaneously: it focuses energy for high directivity while enabling wide-angle electronic scanning. The single reflector structure with multiple focal points replaces what would otherwise require multiple separate antenna systems, providing both high gain and wide scanning capability.
4Stability of the object's composition
If a very long focal length reflector is used to reduce defocusing effects with scan, then defocusing effects are reduced, but the feed element displacement from the focal point increases, requiring larger and more complex feed structures
Solution Approach 1:
Instead of using a single long-focal-length reflector, the system segments the reflector into multiple shorter-focal-length paraboloids. Each segment maintains better focusing properties while the collective arrangement achieves wide scanning, avoiding the need for excessively long focal lengths and complex feed structures.
Solution Approach 2:
The focal length parameter is optimized for each reflector segment rather than using a uniformly long focal length. By adjusting the curvature and focal length of individual segments, the system maintains stable beam shapes across wide scanning angles while keeping feed structures manageable in size and complexity.
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 multifocal reflector antenna system achieves electronic scanning up to ±15-20° with a significantly reduced number of elements, providing cost-effective and flexible beam control for radar, satellite, and terrestrial communication systems, while maintaining high directivity and coverage area.
Implementation Method 1
a multifocal reflector having different focal points and comprising a plurality of segments of paraboloids... configured and operable to receive incident radiation at different angles within a certain angular range and reflecting the incident radiation onto the spaced-apart focal points
Data Source
Figure 1
Figure 2A~2B
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AI summary
The present invention discloses an antenna system comprising a multifocal reflector having at least two reflecting segments having different curvatures defining at least two different spaced apart focal points, such that the multifocal reflector is configured and operable to receive radiation incident on the segments at different incident angles within a certain angular range, and reflect the incident radiation onto the at least two focal points in a focal axis, thereby creating focused radiation formed by at least two differently focused portions of radiation; a phased array feed antenna unit located perpendicularly to the focal axis and comprising a plurality of antenna elements for receiving/transmitting at least two differently focused portions, and a feed network connected to the plurality of the antenna elements for selectively actuating the antenna elements for performing electronic scanning of the space area aimed at detecting target.