Polyamide Radio Wave Absorber for Stable Absorption Peak Control

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Solution Overview

Problem

The existing radio wave absorbers containing magnetic powders and aliphatic polyamides face challenges in maintaining a stable absorption peak of transmission attenuation, leading to deviations in the absorption peak position, which complicates the control of transmission attenuation characteristics.

Innovation Solution

A radio wave absorber is developed with a specific intensity ratio (α/γ) of diffraction intensities of α and γ crystals of the aliphatic polyamide, measured by X-ray diffraction, set at 2.60 or less, to suppress the deviation in the absorption peak position, thereby enhancing control over transmission attenuation characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a magnetic powder and an aliphatic polyamide are used as radio wave absorbing materials, then the radio wave absorber can provide absorption characteristics, but the position of the absorption peak of transmission attenuation deviates and cannot be controlled

Engineering Contradiction:
Improveabsorption peak position stabilityVSAvoidtransmission attenuation characteristics control
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The invention changes the crystal form parameters of the aliphatic polyamide by controlling the intensity ratio (α/γ) of diffraction intensities to be 2.60 or less. This parameter change in the binder's crystal structure stabilizes the absorption peak position of the radio wave absorber, resolving the issue of uncontrolled transmission attenuation characteristics while maintaining effective absorption.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If the kind of magnetic powder is changed to control transmission attenuation characteristics, then the absorption characteristics can be adjusted, but the absorption peak position becomes unstable

Engineering Contradiction:
Improvetransmission attenuation controlVSAvoidabsorption peak position
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The invention uses the aliphatic polyamide binder with controlled crystal form (intensity ratio α/γ ≤ 2.60) as an intermediary to stabilize the magnetic powder particles. This intermediary approach allows the magnetic powder to provide adaptable absorption characteristics while the binder's stable crystal structure prevents absorption peak position deviation.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 proposed solution effectively suppresses the deviation in the absorption peak position, allowing for improved control over the transmission attenuation characteristics of the radio wave absorber, which is essential for enhancing the recognition accuracy of radar systems.

Implementation Method 1

an intensity ratio (α/γ) of a diffraction intensity α of an α crystal of the aliphatic polyamide to a diffraction intensity γ of a γ crystal of the aliphatic polyamide, which are determined by subjecting the radio wave absorber to measurement with an X-ray diffraction method

Methodology Applied
Scientific EffectX-ray diffraction: X-Ray

Implementation Method 2

a radio wave absorber having an absorption peak of transmission attenuation at a frequency to be absorbed

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

Data Source

PatentUS12341249B2Radio wave absorber and radio wave absorbing article
Publication Date: 2025.06.24 FUJIFILM CORP

AI summary

There is provided a radio wave absorber containing a magnetic powder, and an aliphatic polyamide, in which an intensity ratio (α/γ) of a diffraction intensity α of an α crystal of the aliphatic polyamide to a diffraction intensity γ of a γ crystal of the aliphatic polyamide, which are determined by subjecting the radio wave absorber to measurement with an X-ray diffraction method, is 2.60 or less. There is also provided a radio wave absorbing article including this radio wave absorber.