Acoustic Antenna Standing-Wave Channels for Low-Power Underwater Detection
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Solution Overview
Problem
Existing acoustic wave reception systems, such as towed arrays and condenser microphones, face challenges including high energy consumption, complex assembly, limited sensitivity, and interference from flow noise, making them unsuitable for low-power acoustic signal detection and underwater target localization.
Innovation Solution
A device comprising an acoustic antenna with a transmission line configured to function as a condenser microphone, excited by a set of sinusoidal voltages and harmonics, forming directional acoustic-antenna channels through stationary waves, allowing easy separation and demodulation of signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional towed arrays with piezoelectric transducers are used, then acoustic waves can be recorded, but energy-intensive processing and complex hardware assembly are required
Solution Approach 1:
The patent combines the acoustic sensing function and electromagnetic transmission function into a single integrated structure. The distributed condenser microphone elements are formed by conductive elements separated by dielectric material, which also serves as the transmission line structure. This merging eliminates separate piezoelectric transducers, power lines, and multiplexers, significantly reducing hardware complexity while maintaining acoustic detection capability
Solution Approach 2:
The transmission line structure serves multiple functions simultaneously: it acts as the acoustic antenna (condenser microphone), the electromagnetic signal carrier, and the structural support. This multi-functionality eliminates the need for dedicated piezoelectric transducers and separate power transmission infrastructure, reducing both device complexity and assembly requirements
2Measurement precision
If Dirac pulses are applied to distributed condenser microphone, then electromagnetic pulses are amplitude modulated, but the useful length is very short and sensitivity is limited
Solution Approach 1:
The patent employs periodic sinusoidal excitation signals instead of transient Dirac pulses. By applying continuous sinusoidal voltages at multiple frequencies, the system establishes standing waves along the transmission line, creating extended regions of high voltage amplitude that remain active continuously. This periodic action transforms the briefly-sensitive pulse-based system into a continuously-sensitive system with extended useful length
Solution Approach 2:
The system performs preliminary action by pre-establishing standing wave patterns through sinusoidal excitation before acoustic measurement begins. The high-voltage regions are created in advance and maintained continuously, ensuring that the entire transmission line remains in a sensitive state ready to detect acoustic modulations, rather than only briefly during pulse excitation
3Measurement precision
If short pulse excitation is used, then the microphone is sensitive to pressure, but flow noise interference increases and maximum speed is limited
Solution Approach 1:
By using continuous periodic sinusoidal excitation instead of short pulses, the system maintains steady standing wave patterns that create consistent high-voltage regions. This periodic operation at controlled frequencies allows the system to operate at higher speeds while maintaining pressure sensitivity, as the continuous excitation provides stable reference signals that are less susceptible to flow noise interference compared to transient pulses
4Measurement precision
If the transmission line functions as condenser microphone over whole length, then sensitivity is improved, but directional channel formation must be simplified
Solution Approach 1:
The patent uses electromagnetic standing waves (analogous to mechanical vibrations) established by sinusoidal excitation at specific frequencies. These standing waves create fixed patterns of high and low voltage regions along the transmission line, forming directional channels through the natural resonance patterns. This approach simplifies directional channel formation compared to active beamforming algorithms, as the spatial distribution of sensitivity is determined by the physical standing wave patterns
Solution Approach 2:
The system changes parameters by using multiple sinusoidal frequencies with different wavelengths. Each frequency creates standing wave patterns with different spatial distributions, effectively creating different directional channels. By varying the excitation frequency parameter, the system can selectively activate different directional channels along the transmission line, providing simplified channel formation through parameter control rather than complex signal processing
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 provides improved sensitivity, reduced power consumption, and reduced interference from flow noise, enabling effective detection and localization of underwater targets with simplified processing and assembly.
Implementation Method 1
an acoustic antenna which can operate as a condenser microphone distributed along a line of the acoustic antenna
Implementation Method 2
generate an input electromagnetic wave that propagates toward a second longitudinal end of the line
Implementation Method 3
the frequency of the fundamental sinusoidal voltage being defined so that stationary waves are established in the line such that the output electromagnetic wave comprises directional acoustic-antenna channels
Data Source
AI summary
A device for receiving acoustic waves, includes an acoustic antenna able to function as a condenser microphone distributed along a line of the acoustic antenna comprising a conductor and a dielectric, the line being a transmission line or being configured to function as a transmission line when the dielectric makes direct physical contact with another conductor, an exciter configured to apply, in a receiving step, an input voltage to a first longitudinal end of the line so as to generate an input electromagnetic wave that moves toward a second longitudinal end of the line and so as to generate an output electromagnetic wave that moves in the opposite direction to the input electromagnetic wave, the input voltage simultaneously comprising a set of sinusoidal voltages comprising a fundamental sinusoidal voltage and a set of harmonics of the fundamental sinusoidal voltage, the frequency of the fundamental sinusoidal voltage being defined so that stationary waves are established in the line such that the output electromagnetic wave comprises directional acoustic-antenna channels.