Mutually Incoherent Apertures for Radar Antenna Arrays
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Solution Overview
Problem
Existing antenna array designs for radar and radio-frequency applications face challenges in achieving high angular resolution and flexibility due to the need for large physical spaces and synchronization of coherent apertures, which increases complexity and cost, especially at high frequencies, and are prone to phase errors from deformations and vibrations.
Innovation Solution
The design of mutually incoherent apertures allows for the synthesis of antenna element positions and selection of waveforms that eliminate the need for synchronization and phase alignment, enabling flexible use of space and reducing sidelobe levels through mutual sidelobe cancellation, thereby optimizing the effective array factor for applications like automotive radar and synthetic aperture radar.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If coherent apertures are used to achieve high angular resolution, then measurement precision is improved, but device complexity increases due to synchronization requirements
Solution Approach 1:
The patent divides the antenna system into multiple mutually incoherent apertures, each operating independently without synchronization requirements. This segmentation allows each aperture to function autonomously while collectively achieving high angular resolution through incoherent combination, thereby reducing the synchronization complexity inherent in coherent systems.
2Measurement precision
If coherent apertures are used to achieve high angular resolution, then measurement precision is improved, but the required physical space increases
Solution Approach 1:
The patent combines multiple mutually incoherent apertures to achieve the angular resolution performance previously requiring a single large coherent aperture. By merging the effective contributions of multiple smaller incoherent apertures, the system attains equivalent or superior resolution while utilizing space more efficiently and reducing the total physical footprint.
3Measurement precision
If coherent apertures are used, then angular resolution is improved, but reliability decreases due to phase errors from deformations and vibrations
Solution Approach 1:
Instead of attempting to maintain phase coherence despite deformations and vibrations (the conventional approach), the patent inverts the strategy by deliberately operating in the incoherent regime. By abandoning phase alignment requirements, the system becomes inherently immune to phase errors caused by mechanical deformations and vibrations, thereby improving reliability while maintaining angular resolution through statistical combination of multiple apertures.
4Measurement precision
If synchronization is implemented for coherent apertures, then angular resolution is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent extracts and eliminates the synchronization and phase alignment requirements from the system design. By operating with mutually incoherent apertures, the system removes the need for precise manufacturing and assembly tolerances required for phase coherence, thereby reducing manufacturing precision requirements while maintaining high angular resolution through incoherent signal combination.
Data Source
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AI summary
In a method for synthesis of antenna array layouts for radar and radio-frequency applications, the layouts are formed to comprise a given number of mutually incoherent apertures. For given space specifications for each aperture, number of transmit and receive antennas and field of views of the antennas, a design method is applied including: providing a metric with ambiguity functions based on a signal model that includes random initial phases between apertures, and selection of transmit and receive antenna locations according to said metric based on optimization of the ambiguity functions such that a sidelobe level and/or features dependent on the sidelobe level associated to said ambiguity functions over a number of dimensions corresponding to one or several parameters of interest, including azimuth and/or elevation, is minimized. A similar method is provided for selection of waveform, including frequency selection in stepped frequency waveforms, and pulse transmission times, for transmitters in a set of mutually incoherent apertures for radar and radio-frequency applications.