Flexible EM Wave Absorbing Composition for Millimeter-Wave Shielding

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Solution Overview

Problem

Current electromagnetic-wave absorbing compositions and absorbers are inadequate for effectively shielding high-frequency electromagnetic waves in the millimeter-wave band and cannot be easily applied to non-flat surfaces or circuit boards in a deformable form.

Innovation Solution

A composition and absorber using a rubber binder, particulate carbon material, and magnetic iron oxide that magnetically resonates in the millimeter-wave band, allowing for a paste-like application and nonresonant, flexible sheet-shaped absorber with enhanced electromagnetic wave absorption and reduced electric resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional electromagnetic-wave absorbing compositions are used, then electromagnetic wave absorption is achieved, but they cannot effectively absorb high-frequency electromagnetic waves in the millimeter-wave band

Engineering Contradiction:

Improveelectromagnetic wave absorption effectivenessVSAvoidfrequency band coverage

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent changes the magnetic properties of the iron oxide particles by controlling their crystal structure (gamma-phase) and particle size (0.1-10 micrometers) to achieve magnetic resonance in the millimeter-wave frequency band (30-300 GHz). This parameter optimization enables effective absorption of high-frequency electromagnetic waves that conventional materials cannot absorb.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite material system consisting of magnetic iron oxide particles dispersed in a binder resin matrix. This composite structure combines the electromagnetic wave absorbing properties of magnetic iron oxide with the mechanical properties of the binder, achieving both effective millimeter-wave absorption and practical applicability.

Inventive Principle:

Principle #40Composite materials

2Reliability

If block-shaped or planar electromagnetic-wave absorbers are used, then electromagnetic wave shielding is achieved, but they cannot conform to non-flat surfaces

Engineering Contradiction:

Improveelectromagnetic wave shielding effectivenessVSAvoidadaptability to surface geometry

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent formulates the electromagnetic wave absorbing composition as a paste that can be applied as a thin film coating on circuit boards and other surfaces. The paste formulation with binder resin allows the coating to conform to non-flat surfaces while maintaining electromagnetic wave absorption effectiveness.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent creates a deformable paste formulation that can be dynamically applied to various surface geometries. The composition remains workable during application and then sets into a functional coating, adapting to the underlying surface shape while maintaining shielding performance.

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

The solution effectively converts high-frequency electromagnetic waves into heat, providing high electromagnetic wave attenuation and flexibility, enabling effective shielding of electromagnetic waves in the millimeter-wave band while preventing short circuits and maintaining low electric resistance.

Implementation Method 1

magnetic iron oxide that magnetically resonates in a frequency band in or above a millimeter-wave band as an electromagnetic-wave absorbing material

Methodology Applied

Scientific EffectMagnetic resonance: Resonance

Implementation Method 2

converts high-frequency electromagnetic waves into heat, providing high electromagnetic wave attenuation

Methodology Applied

Scientific EffectElectromagnetic wave absorption: Absorption (EM radiation)

Implementation Method 3

the decrease in the electric resistance of the electromagnetic-wave absorbing composition can be eliminated or reduced while enhancing the permittivity

Methodology Applied

Scientific EffectPermittivity enhancement: Dielectric Permittivity

Data Source

PatentUS11804659B2Electromagnetic wave absorbing composition, and electromagnetic wave absorption body

Publication Date: 2023.10.31 MAXELL LTD

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.