Planar Transducer Array Configuration for Broadband 3D Beamforming
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Solution Overview
Problem
Existing methods for configuring planar transducer arrays for broadband signal processing in three-dimensional beamforming face challenges in achieving robust superdirectivity at low frequencies and avoiding grating lobes at high frequencies, particularly in wide frequency ranges, due to excessive computational load and inadequate robustness against transducer imperfections.
Innovation Solution
A method combining superdirective beamforming for low-frequency components with a sparse aperiodic array arrangement for high-frequency components, optimized using a hybrid iterative process that minimizes a cost function through analytical calculus for FIR filter coefficients and stochastic calculus for transducer positions, incorporating a probability density function to account for transducer characteristics and ensuring beam pattern integrity across steering directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If superdirective beamforming is used for low-frequency components, then directivity is improved, but robustness against transducer imperfections deteriorates
Solution Approach 1:
The patent applies parameter changes by modifying the beamforming weights and transducer configuration parameters to achieve superdirectivity while incorporating robustness constraints. The optimization process adjusts these parameters to balance directivity enhancement with tolerance to transducer imperfections, transforming the system from a purely performance-oriented design to one that accounts for practical limitations.
2Object-affected harmful factors
If sparse aperiodic array arrangement is used for high-frequency components, then grating lobes are avoided, but device complexity increases
Solution Approach 1:
The patent employs asymmetry by implementing a sparse aperiodic array configuration where transducers are positioned at non-uniform intervals and asymmetric locations within the array aperture. This asymmetric arrangement eliminates the periodicity that causes grating lobes, achieving clean beam patterns at high frequencies despite the increased configurational complexity.
Solution Approach 2:
The patent transitions from uniform one-dimensional spacing to two-dimensional sparse positioning, adding spatial dimensionality to the array configuration. This dimensional expansion allows transducers to be placed optimally in both x and y directions, creating a planar sparse array that avoids grating lobes while managing complexity through intelligent geometric distribution.
3Adaptability or versatility
If filter-and-sum beamforming is used for broadband signal processing, then frequency range coverage is improved, but computational load increases
Solution Approach 1:
The patent segments the broadband frequency range into multiple subbands, applying filter-and-sum beamforming independently to each segment. This segmentation approach processes different frequency portions separately, reducing the computational complexity of handling the entire broadband spectrum simultaneously while maintaining comprehensive frequency coverage through the aggregation of segmented results.
Data Source
AI summary
A method of configuring planar transducer arrays for broadband signal processing by 3D beamforming, wherein a superdirective beamforming technique for low-frequency signal components is combined with a sparse and aperiodic array pattern for high-frequency components in a predetermined frequency range, and wherein the positions of the individual transducers at the aperture of the array and the FIR filter coefficients are further optimized in parallel, by a hybrid iterative process including an analytical calculus for determining the FIR filter coefficients and a stochastic calculus for determining the transducer positions at the aperture of the planar transducer arrays, by minimization of a cost function.