Magnetic Probe Measurement for Simultaneous Permeability and Permittivity

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Solution Overview

Problem

Existing methods struggle to simultaneously measure both permeability and permittivity of electromagnetic materials at high frequencies, particularly for materials like radio wave absorbers and shield materials, with a demand for improved accuracy.

Innovation Solution

A measurement device and method utilizing a probe with a signal transmission line, a magnetic field application unit, and a signal measurement instrument, along with a computer device for processing, to measure permeability and permittivity by applying and removing a DC magnetic field, enabling simultaneous and accurate determination of both properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional measurement methods using coils or transmission lines are used, then measurement capability is provided, but simultaneous measurement of both permeability and permittivity is not achieved

Engineering Contradiction:
Improvesimultaneous measurement accuracyVSAvoidmeasurement capability
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The measurement device integrates both permeability measurement and permittivity measurement capabilities into a single system. The probe includes both a coil portion for permeability measurement and transmission line portions for permittivity measurement, allowing simultaneous characterization of electromagnetic materials with both magnetic and dielectric properties.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If magnetic field application is added to the measurement system, then permeability measurement accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvepermeability measurement accuracyVSAvoidsystem structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The magnetic field application unit is integrated into the probe structure itself, with the coil serving dual purposes as both the measurement sensor and the magnetic field application mechanism. This merging of functions reduces overall system complexity while maintaining measurement accuracy.

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If a probe with both coil and transmission line is used, then both permeability and permittivity can be measured, but probe design complexity increases

Engineering Contradiction:
Improvedual measurement capabilityVSAvoidprobe structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The probe is divided into distinct functional segments: a coil portion for permeability measurement and transmission line portions for permittivity measurement. This segmentation allows each component to be optimized independently while maintaining overall system integration, managing design complexity through modular functional division.

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

Enables simultaneous and accurate measurement of permeability and permittivity of electromagnetic materials, improving measurement accuracy by accounting for magnetic field influences.

Implementation Method 1

a magnetic field application unit configured to apply a DC magnetic field to magnetically saturate the object to be measured

Methodology Applied
Scientific EffectMagnetic saturation: Magnetic Saturation

Data Source

PatentEP4141456B1Measurement device and measurement method for measuring magnetic permeability and dielectric constant
Publication Date: 2025.12.03 TOHOKU UNIV
  • EP4141456B1 patent drawingFigure 1
  • EP4141456B1 patent drawingFigure 2(a)~2(b)
  • EP4141456B1 patent drawingFigure 3(a)~3(b)

AI summary

The measurement device for measuring permeability and permittivity of an object, includes: a probe in which a signal transmission line is formed and on which the object is capable of being disposed close to or in contact with the signal transmission line; a magnetic-field application unit configured to apply a magnetic-field to the object; a signal measurement instrument configured to measure a signal transmitted through the signal transmission line in each state in which the object is disposed and not disposed on the signal transmission line and in each state in which the magnetic-field is applied and not applied; a permeability processing unit configured to obtain the permeability of the object; and a permittivity processing unit configured to obtain the permittivity of the object, the both units obtaining based on the signal transmitted through the signal transmission line in each state in which the magnetic-field is applied and not applied.