Flexible Millimeter-Wave Absorbing Composition Without Reflective Layer

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Solution Overview

Problem

Existing electromagnetic-wave absorbing compositions and absorbers fail to effectively shield high-frequency electromagnetic waves in the millimeter-wave band and are not flexible enough to conform to non-flat surfaces or apply as a paste-like coating.

Innovation Solution

An electromagnetic-wave absorbing composition and absorber using a rubber binder, particulate carbon material, and magnetic iron oxide that magnetically resonates in the millimeter-wave band, allowing for flexible, nonresonant absorption and application as a paste or sheet.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional electromagnetic-wave absorbers (block-shaped or planar) are used, then electromagnetic-wave absorption is achieved, but flexibility and ability to conform to non-flat surfaces are lost

Engineering Contradiction:
ImproveflexibilityVSAvoidform factor
Core Design Contradiction:
Ease of operationVSShape

Solution Approach 1:

The patent employs a rubber binder as the matrix material to create a flexible, sheet-shaped electromagnetic-wave absorber that can be easily deformed and conform to non-flat surfaces. This flexible matrix allows the absorber to be applied in various forms including sheets and paste-like coatings, resolving the contradiction between maintaining absorption functionality and achieving flexibility.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The invention creates a composite material system combining rubber binder, magnetic iron oxide particles, and carbon material particles. This composite structure integrates the flexibility of rubber with the electromagnetic-wave absorbing properties of magnetic particles and carbon materials, enabling both form adaptability and functional performance.

Inventive Principle:
Principle #40Composite materials

2Adaptability or versatility

If electromagnetic-wave absorbers are made rigid for structural stability, then manufacturing precision is improved, but adaptability to different application forms is reduced

Engineering Contradiction:
Improveapplication formVSAvoidstructural stability
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent utilizes the viscoelastic properties of rubber that change with temperature and processing conditions. During manufacturing, the rubber can be softened for molding into desired shapes, then stabilized upon cooling or curing. This parameter change allows the material to be easily formed into various application forms while maintaining structural stability in the final product.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If magnetic iron oxide particles are used for high-frequency absorption, then electromagnetic-wave absorption in millimeter-wave band is achieved, but material cost and complexity increase

Engineering Contradiction:
Improveabsorption effectivenessVSAvoidmaterial composition
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines magnetic iron oxide particles with carbon material particles in a rubber matrix to create a composite absorber. The carbon materials (such as carbon black or graphite) provide additional absorption mechanisms and can enhance the overall effectiveness while potentially reducing the required amount of expensive magnetic iron oxide, thus managing material complexity and cost.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention distributes different types of particles (magnetic iron oxide and carbon materials) throughout the rubber matrix, allowing each component to contribute its specific absorption properties locally. This local quality approach ensures comprehensive absorption coverage across the millimeter-wave band while optimizing the overall material composition.

Inventive Principle:
Principle #3Local quality

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 composition and absorber efficiently convert high-frequency electromagnetic waves into heat, providing effective shielding with flexibility and elasticity, reducing the risk of short circuits while maintaining high electromagnetic-wave attenuation.

Implementation Method 1

magnetic iron oxide that magnetically resonates in a frequency band in or above a millimeter-wave band

Methodology Applied
Scientific EffectMagnetic resonance: Resonance

Implementation Method 2

electromagnetic-wave absorbing composition and an electromagnetic-wave absorber that have properties of absorbing electromagnetic waves

Methodology Applied
Scientific EffectElectromagnetic wave absorption: Absorption (EM radiation)

Implementation Method 3

a filler made of a particulate carbon material

Methodology Applied
Scientific EffectDielectric heating: Dielectric Heating

Data Source

PatentEP3657922B1Electromagnetic wave absorbing composition, and electromagnetic wave absorption body
Publication Date: 2026.01.14 MAXELL LTD
  • EP3657922B1 patent drawingFigure 1
  • EP3657922B1 patent drawingFigure 2
  • EP3657922B1 patent drawingFigure 3

AI summary

Provided are an electromagnetic-wave absorbing composition that can favorably absorb electromagnetic waves of high frequencies in or above a millimeter-wave band and that can be applied to a desired portion in the form of a paste, and an easily deformable electromagnetic-wave absorber having flexibility. The electromagnetic-wave absorbing composition includes a rubber binder, a filler made of a particulate carbon material, and a magnetic iron oxide that magnetically resonates in a frequency band in or above a millimeter-wave band as an electromagnetic-wave absorbing material. The electromagnetic-wave absorber includes a rubber binder 1b, a filler 1c made of a particulate carbon material, and a magnetic iron oxide that magnetically resonates in a frequency band in or above a millimeter-wave band as an electromagnetic-wave absorbing material 1a, and is a nonresonant-type electromagnetic-wave absorber that is not provided with a reflective layer for reflecting incident electromagnetic waves.