Dielectric Spectroscopy Sensor Impedance Mismatch Sensitivity

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Solution Overview

Problem

Dielectric spectroscopy sensors using transmission lines like coaxial sensors face limitations in measurement sensitivity due to the need for matched characteristic impedance between the sensor and the dielectric spectroscopy system, which restricts the sensitivity of reflected wave measurements.

Innovation Solution

A dielectric spectroscopy sensor with a transmission line having one end connected to a dielectric spectroscopy system with a first characteristic impedance and the other end serving as a measurement surface with a second characteristic impedance different from the first, allowing for improved sensitivity by adjusting the characteristic impedance at the measurement surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the transmission line is designed with matched characteristic impedance to reduce reflection loss, then energy loss is reduced, but measurement sensitivity of reflected wave is limited

Engineering Contradiction:

Improvereflection lossVSAvoidmeasurement sensitivity

Core Design Contradiction:

Loss of energyVSMeasurement precision

Solution Approach 1:

The patent changes the characteristic impedance parameter of the transmission line from a fixed matched value to a variable design parameter. By optimizing the characteristic impedance to a specific value different from the system impedance, the patent enhances reflected wave sensitivity while managing reflection loss through the impedance transformation ratio. This parameter change allows the transmission line to function as an impedance transformer that improves measurement sensitivity.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The transmission line acts as an intermediary component between the dielectric spectroscopy system and the measurement target. By introducing this intermediate element with specific impedance characteristics, the patent enables impedance transformation that mediates between the system impedance and the optimal sensing impedance, thereby improving measurement sensitivity without direct mismatch at the system interface.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If the characteristic impedance at the measurement surface is optimized for sensitivity, then measurement sensitivity is improved, but impedance mismatch causes reflection loss

Engineering Contradiction:

Improvemeasurement sensitivityVSAvoidreflection loss

Core Design Contradiction:

Measurement precisionVSLoss of energy

Solution Approach 1:

The patent optimizes the characteristic impedance parameter at the measurement surface to a specific value that maximizes sensitivity to dielectric constant changes. This parameter optimization is achieved by adjusting the transmission line dimensions and materials to create the desired impedance transformation ratio, balancing sensitivity improvement against acceptable reflection loss.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces dynamic impedance transformation through the transmission line, where the impedance changes along the length of the transmission line from the system interface to the measurement surface. This dynamic impedance profile allows the system to maintain good matching at the interface while achieving optimal sensitivity at the measurement point through gradual impedance transformation.

Inventive Principle:

Principle #15Dynamics

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 enhances the measurement sensitivity of the dielectric spectroscopy sensor by allowing the characteristic impedance at the measurement surface to be optimized, leading to improved accuracy and detection limits in dielectric constant measurements.

Implementation Method 1

a transmission line whose first end has a first characteristic impedance and second end has a second characteristic impedance different from the first characteristic impedance

Methodology Applied

Scientific EffectImpedance transformation: Electrical Impedance Tomography

Implementation Method 2

the second end serves as a measurement surface for measuring a dielectric constant of a measurement target object

Methodology Applied

Scientific EffectDielectric spectroscopy: Dielectric Permittivity

Data Source

PatentUS20250076234A1Dielectric Spectroscopy Sensor

Publication Date: 2025.03.06 NIPPON TELEGRAPH & TELEPHONE CORP

AI summary

The present invention includes a transmission line in which a connection line and an impedance converter are connected and a measurement surface which is brought into direct or indirect contact with a measurement target object M and outputs an electromagnetic wave to the measurement target object. The connection line has a first characteristic impedance that is the same as that of a dielectric spectroscopy system. An end on the connection line side of the impedance converter has the first characteristic impedance, and an end on the measurement surface side thereof has a second characteristic impedance different from the first characteristic impedance.