Dual-Probe TDR Sensor for Accurate Water Content Measurement

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Solution Overview

Problem

Time-domain reflectometry (TDR) methods for measuring water content in media, such as soil, are affected by gaps near the probes, leading to inaccurate relative permittivity measurements.

Innovation Solution

A sensor device with a first and second probe, where the second probe is situated at a specified distance from the first probe, and both include antenna sections for transmission and reception, with a measurement unit generating a signal that accounts for electromagnetic wave propagation characteristics between the probes, minimizing the impact of gaps and preventing resonance-related measurement errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If TDR measures relative permittivity using electromagnetic wave propagation characteristics near a single probe, then the measurement method is simple, but gaps near the probe have a great impact on measurement accuracy

Engineering Contradiction:

Improvemeasurement method simplicityVSAvoidrelative permittivity measurement accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The single probe measurement system is segmented into two separate probes: a transmission probe and a reception probe. This segmentation allows the electromagnetic wave to propagate through the medium between the probes rather than measuring near a single probe, thereby reducing the impact of gaps while maintaining measurement simplicity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The medium itself acts as an intermediary between the transmission and reception probes. By measuring the electromagnetic wave propagation characteristics through the medium rather than near the probe surface, the system eliminates the gap-related measurement errors while keeping the overall measurement approach simple.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Volume of moving object

If probes are placed close together for compact sensor design, then device size is reduced, but resonance of the probes decreases measurement accuracy

Engineering Contradiction:

Improvesensor device sizeVSAvoidmeasurement accuracy

Core Design Contradiction:

Volume of moving objectVSMeasurement precision

Solution Approach 1:

The reception function is extracted from the transmission probe and assigned to a separate reception probe. This allows the probes to be positioned at an optimal distance that avoids resonance while maintaining a compact overall sensor design, as the electromagnetic wave propagation path is clearly defined between the two separate probes.

Inventive Principle:

Principle #2Taking out (Extraction)

3Device complexity

If a single probe is used for both transmission and reception, then the device configuration is simple, but gap effects cannot be minimized

Engineering Contradiction:

Improveprobe configuration complexityVSAvoidrelative permittivity measurement accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The single probe is segmented into two functionally separate probes: one dedicated to transmission and the other to reception. This segmentation increases measurement accuracy by allowing the electromagnetic wave to propagate through the medium between the probes, minimizing gap effects, while the overall device configuration remains relatively simple.

Inventive Principle:

Principle #1Segmentation

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

This configuration improves the accuracy of relative permittivity and water content measurements in media by reducing the impact of gaps and resonance issues, providing more reliable data compared to traditional TDR methods.

Implementation Method 1

transmitting an electromagnetic wave along a metallic probe embedded in a medium

Methodology Applied

Scientific EffectElectromagnetic wave propagation: Electromagnetic Induction

Implementation Method 2

calculating a water amount in the medium from relative permittivity measured using its reflection response

Methodology Applied

Scientific EffectElectromagnetic wave reflection: Reflection

Data Source

PatentUS20240377435A1Sensor device, water amount measurement device, water amount measurement method, information processing device, and information processing method

Publication Date: 2024.11.14 SONY GROUP CORP

AI summary

A sensor device according to an embodiment of the present technology includes a sensor head and a measurement unit. The sensor head includes a first probe and a second probe, the first probe including a first antenna section used for transmission, the second probe including a second antenna section used for reception, the second probe being situated at a specified distance from the first probe and facing the first probe. The measurement unit includes a signal generator that generates a measurement signal that includes information regarding characteristics of a propagation of an electromagnetic wave in a medium between the first and second antenna sections.