Digital Beamforming Radar Subarray Architecture
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Solution Overview
Problem
Current radar systems, particularly automotive radar systems, face limitations in achieving wide angle coverage with narrow beams and high update rates due to high costs, excessive RF loss, and reliability issues with mechanically scanned antennas, while conventional electronically scanned antennas using discrete phase shifters are expensive and inefficient.
Innovation Solution
A high performance and low cost electronically scanned radar system employing a uniform overlapped subarray feed network, time multiplexed switch matrix, and restructured digital signal processor to minimize the number of receivers, eliminate grating lobes, and compensate for target motion-induced phase shifts, enabling enhanced sensitivity and wide angle coverage with narrow beams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If discrete phase shifters are used for electronic scanning, then scanning speed and field of view are improved, but cost and RF loss increase excessively
Solution Approach 1:
The patent replaces mechanical scanning systems with electronic scanning using a digital beamforming architecture. Individual antenna elements are downconverted and sampled, with beam scanning performed by a digital signal processor, eliminating the need for discrete phase shifters and their associated RF losses while maintaining fast scanning capabilities
Solution Approach 2:
The patent changes the operating parameters by performing downconversion and sampling at the individual antenna element level before digital beamforming. This parameter change allows electronic scanning to be achieved through digital signal processing rather than analog phase shifting, reducing RF loss while maintaining scanning speed
2Measurement precision
If a large array with numerous antenna elements is used to achieve narrow beams and wide coverage, then beam precision and field of view are improved, but the number of required receivers increases cost excessively
Solution Approach 1:
The patent merges the functions of multiple receivers into a single digital signal processor that performs beam scanning and signal processing for all antenna elements. By combining individual element outputs and performing digital beamforming, the system achieves narrow beams and wide coverage with a minimal number of receivers, dramatically reducing system cost
Solution Approach 2:
The digital signal processor serves multiple functions: it performs downconversion, sampling, beam scanning, and signal processing for all antenna elements. This multi-functional approach eliminates the need for dedicated receivers for each element, reducing the number of receivers while maintaining beam precision and coverage
3Adaptability or versatility
If conventional digital beamforming architectures are used, then electronic scanning is achieved, but field of view is inadequate and grating lobes appear
Solution Approach 1:
The patent segments the antenna array into individual elements that are independently downconverted and sampled. This segmentation allows for optimized element spacing and independent signal processing, enabling achievement of wide field of view while controlling grating lobe formation through digital beamforming techniques
Solution Approach 2:
The patent uses digital signal processing to create virtual beam copies at different steering angles without physical beamforming hardware. This digital copying approach allows wide field of view coverage while maintaining control over grating lobe positions and amplitudes through algorithmic manipulation
Data Source
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AI summary
Digital beamfonning is provided for use with electronically scanned radar. In an aspect, the present invention provides enhanced sensitivity, wide angle or field of view (FOV) coverage with narrow beams, minimized number of receivers, reduced sidelobes, eliminated grating lobes and beam compensation for target motion. In an aspect, the present invention employs a uniform overlapped subarray feed network (420), a time multiplexed switch matrix (424), and a restructured digital signal processor (430). Antenna channels share a receiver (406), rather than maintain a dedicated receiver for each antenna element, as in conventional systems. In an aspect, Doppler/frequency filtering (432) is performed on each antenna element or subarray output prior to digital beamforming (436). Further, Doppler compensation (434) is employed following Doppler/frequency filtering (432), followed by digital beamforming (436).