Modal Acoustic Array Transducer for Constant Beam Patterns
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Solution Overview
Problem
Existing acoustic transducer arrays struggle to produce directional steered beam patterns with desirable beam width, side lobe, and null structural properties across a broad frequency range, particularly in achieving constant beam patterns and efficient radiation modes.
Innovation Solution
An electromechanical transducer array apparatus comprising multiple acoustic transducers arranged to excite monopole, dipole, and quadrupole radiation modes, combined in specific proportions to achieve a constant beam pattern with adjustable voltage distributions, allowing for beam steering and stable performance over a broad frequency range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional planar, spherical, or cylindrical transducer arrays are used to form directional beams, then beam directionality can be achieved, but the beam pattern varies with frequency and cannot maintain constant beam width over broadband operation
Solution Approach 1:
The transducer array is segmented into multiple independent transducer elements arranged in a specific geometric configuration. Each element can be independently controlled to excite different radiation modes (monopole, dipole, quadrupole), allowing the superposition of these modes to create a frequency-invariant beam pattern through modal synthesis
Solution Approach 2:
The invention changes the operational parameters by controlling the amplitude and phase of each transducer element to excite specific radiation modes. By adjusting the modal coefficients and applying frequency-dependent weighting factors, the beam pattern parameters remain constant across a broad frequency range
2Reliability
If multiple radiation modes (monopole, dipole, quadrupole) are combined to achieve improved directional patterns, then beam width and side lobe properties improve, but the system complexity increases
Solution Approach 1:
The transducer elements serve multiple functions: they can individually excite different radiation modes (monopole, dipole, quadrupole) and can be configured in various geometric arrangements (planar, spherical, cylindrical). This multi-functionality allows a single array structure to achieve multiple beam patterns and operational modes without requiring separate dedicated structures for each function
3Reliability
If transducers are arranged to excite specific radiation modes with controlled voltage distributions, then directional beam patterns with reduced side lobes are achieved, but the manufacturing and setup precision requirements increase
Solution Approach 1:
The system incorporates feedback mechanisms where the actual beam pattern is measured and compared to the desired pattern. The voltage distributions and modal coefficients are then adjusted based on this feedback to optimize side lobe reduction and maintain the intended beam characteristics, compensating for manufacturing tolerances and positioning variations
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 enables the generation of improved directional beam patterns with reduced side lobes and consistent performance across a wide frequency range, suitable for applications in sonar systems and other acoustic energy transmission and reception scenarios.
Implementation Method 1
eight piezoelectric ceramic stacks each driving a piston
Implementation Method 2
cause monopole, dipole and quadrupole radiation modes which, combined together in defined proportions, form the desired constant beam pattern
Data Source
AI summary
A transduction apparatus, which employs an array of individual transducers that generates multiple acoustic radiation modes, is described. These modes are used together to yield directional steered beam patterns. In one embodiment separate transducers, clustered in the form of a ring array, are used together to generate wide and narrow cardioid type beam patterns through combined monopole, dipole and quadrupole radiation modes in the medium, along with at least one tail mass.