Passive Cooperative Acoustic Target Sensing in Harsh Environments

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Solution Overview

Problem

Existing wireless sensing technologies are ineffective in harsh environments, such as those with high temperatures or within Faraday cages, due to reliance on electromagnetic wave propagation, and lack cost-effective, energy-autonomous solutions for measuring physical quantities like force, temperature, current, voltage, flow, and humidity.

Innovation Solution

A system utilizing a passive cooperative target with a resonator connected to an electroacoustic transducer forms an acoustic channel, using software-defined radar for interrogation and a high-Q resonator to transmit response signals via ultrasound, eliminating the need for active components or power sources, and operating in acoustic channels across various frequency ranges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If electromagnetic wave propagation is used for wireless sensing, then wireless measurement capability is achieved, but effectiveness in harsh environments (high temperature, Faraday cages) deteriorates

Engineering Contradiction:

Improvewireless sensing capabilityVSAvoideffectiveness in harsh environments

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent replaces electromagnetic wave propagation with acoustic wave propagation. The electroacoustic transducer converts electrical signals to acoustic waves, which travel through the acoustic channel to the resonator, then back to the transducer for detection. This acoustic mechanism works reliably in harsh environments including high temperatures and within Faraday cages, eliminating the limitations of electromagnetic waves in these conditions.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Power

If active components and power sources are used in the sensing system, then signal transmission capability is improved, but cost-effectiveness and energy autonomy deteriorate

Engineering Contradiction:

Improvesignal transmission capabilityVSAvoidcost-effectiveness and energy autonomy

Core Design Contradiction:

PowerVSEase of manufacture

Solution Approach 1:

The passive cooperative target system is energy-autonomous, requiring no external power source or active components. The resonator and electroacoustic transducer form a self-contained system where the interrogating device sends acoustic signals that elicit responses from the resonator without requiring power transfer. This eliminates costs associated with power supply systems and active electronics, making the solution cost-effective while maintaining signal transmission capability.

Inventive Principle:

Principle #25Self-service

3Measurement precision

If electromagnetic sensing methods are used, then measurement capability is achieved, but measurement precision in harsh conditions deteriorates

Engineering Contradiction:

Improvetemperature resolutionVSAvoidimpact of harsh conditions

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent achieves high measurement precision (0.17°C temperature resolution) by using acoustic wave propagation instead of electromagnetic waves. The acoustic channel and resonator system provides stable signal transmission and detection in harsh conditions, enabling precise measurements of physical quantities such as temperature, force, current, voltage, flow, and humidity without the degrading effects that limit electromagnetic sensing methods.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

Enables precise, energy-autonomous measurements in harsh conditions, achieving a temperature resolution of 0.17°C and a range of 350 mm, suitable for applications in moving parts, enclosed cavities, and submerged environments.

Implementation Method 1

the first electroacoustic transducer and the second electroacoustic transducer form an acoustic channel

Methodology Applied

Scientific EffectAcoustic wave propagation: Sound

Implementation Method 2

the resonator can store at least part of the energy of the interrogation signal due to the high quality until an environmental signal reflection of the interrogation signal has decayed

Methodology Applied

Scientific EffectResonance: Resonance

Implementation Method 3

a first electroacoustic transducer connected to an interrogation unit... at least one second electroacoustic transducer which is electrically connected to a resonator

Methodology Applied

Scientific EffectElectroacoustic conversion: Piezoelectric Effect

Data Source

PatentEP3665450B1Measuring apparatus with a passive cooperative target

Publication Date: 2025.07.23 ALBERT LUDWIGS UNIV FREIBURG

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AI summary

The invention relates to a system comprising a first electroacoustic converter, which is connected to a query unit, and at least a second electroacoustic converter, which is connected to a resonator. The first electroacoustic converter and the second electroacoustic converter form an acoustic channel, and the second electroacoustic converter together with the resonator forms a passive cooperative target which, when a query signal is received, sends a response signal to the query unit via the acoustic channel, the query signal having a higher energy than the response signal.