Multilayer Radome Skin Structure for RF Transmission and Adhesion

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Solution Overview

Problem

Cyanate ester resin used in radomes has hard and brittle properties with weak adhesive force, leading to manufacturing yield issues and damage susceptibility.

Innovation Solution

A multilayer radome structure with a first fiber reinforced plastic layer containing cyanate ester resin and a second fiber reinforced plastic layer containing epoxy resin, where the second layer acts as an adhesive, bonded to the core member, with a thickness ratio of the second layer to all skin layers being 50% or less and a thickness of 1/4 or less of the free space wavelength at the center frequency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cyanate ester resin is used for the skin layer to achieve low dielectric constant and improved radio wave transmission, then radio wave transmission performance is improved, but adhesive force with the core member becomes weak and manufacturing yield deteriorates

Engineering Contradiction:
Improveradio wave transmission performanceVSAvoidadhesive force
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The skin layer is segmented into two distinct layers: a first fiber reinforced plastic layer containing cyanate ester resin for radio wave transmission, and a second fiber reinforced plastic layer containing epoxy resin for adhesion to the core member. This segmentation allows each layer to specialize in its respective function without compromise

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the skin layer are assigned different material properties: the outer surface (first layer) uses cyanate ester resin with low dielectric constant for optimal radio wave transmission, while the inner surface (second layer) uses epoxy resin with high adhesive force for strong bonding to the core member

Inventive Principle:
Principle #3Local quality

2Reliability

If cyanate ester resin is used for the skin layer, then radio wave transmission performance is improved, but the material becomes hard and brittle leading to easy damage

Engineering Contradiction:
Improveradio wave transmission performanceVSAvoidstructural integrity
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The skin layer is divided into two layers with different material properties: the first layer (cyanate ester resin) provides radio wave transmission performance, while the second layer (epoxy resin) provides structural flexibility and damage resistance, creating a composite structure that balances both requirements

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The skin layer is formed as a composite structure combining two different fiber reinforced plastic materials: cyanate ester resin-based material for low dielectric constant and epoxy resin-based material for toughness and damage resistance, achieving properties superior to either material alone

Inventive Principle:
Principle #40Composite materials

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

Improves radio wave transmission performance and strength by using cyanate ester resin for low dielectric constant and epoxy resin for adhesion, maintaining transmission performance while enhancing structural integrity.

Implementation Method 1

a first fiber reinforced plastic layer containing a cyanate ester resin and a fiber material

Methodology Applied
Scientific EffectDielectric constant: Dielectric Permittivity

Implementation Method 2

a second fiber reinforced plastic layer containing an epoxy resin and a fiber material... the second fiber reinforced plastic layer functions as an adhesive layer that bonds the core member and the first fiber reinforced plastic layer together

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP4280377B1radome
Publication Date: 2025.06.25 THE YOKOHAMA RUBBER CO LTD
  • EP4280377B1 patent drawingFigure 1
  • EP4280377B1 patent drawingFigure 2
  • EP4280377B1 patent drawingFigure 3

AI summary

To improve quality of a radome using a cyanate ester resin for a skin layer. A radome (10) is formed of a multilayer structure in which a plurality of skin layers are layered on a surface of a core member (12). The plurality of skin layers include a first fiber reinforced plastic layer (20) containing the cyanate ester resin and a fiber material and a second fiber reinforced plastic layer (16) containing an epoxy resin and a fiber material. The second fiber reinforced plastic layer (16) is disposed at a position in contact with the surface of the core member (12). A proportion of a thickness of the second fiber reinforced plastic layer (16) to a thickness of all of the skin layers is preferably 50% or less.