Magnetic Sheath Communication Cable for Flexible EMI Shielding
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Solution Overview
Problem
Conventional communication cables with magnetic sheath layers for electromagnetic shielding suffer from low flexibility, leading to damage and reduced noise shielding performance when bent or exposed to high temperatures, particularly in environments like automotive vehicles.
Innovation Solution
A communication cable design featuring a magnetic sheath layer with a lower tensile modulus of elasticity than the insulation layer, composed of organic polymers and powdered magnetic materials, with a higher low melting point polymer content, ensuring high flexibility and reduced load application on the metal foil during bending and high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a magnetic sheath layer is provided on the outer periphery of the metal foil for electromagnetic shielding, then the shielding performance is improved, but the flexibility of the cable deteriorates and the metal foil may be damaged during bending
Solution Approach 1:
The patent changes the physical parameters of the magnetic sheath layer by controlling the particle size distribution of magnetic powder (mixing fine particles of 1-10 μm with coarse particles of 10-100 μm) and adjusting the polymer matrix composition. This creates a layered structure where fine particles fill gaps between coarse particles, achieving both flexibility and shielding performance through parameter optimization rather than simply increasing magnetic material content.
Solution Approach 2:
The patent uses composite materials by combining magnetic powder particles with a polymer matrix (such as polyolefin) to form the magnetic sheath layer. The composite structure allows the polymer to provide flexibility and toughness while the magnetic powder provides electromagnetic shielding, resolving the contradiction between shielding performance and cable flexibility.
2Object-affected harmful factors
If a magnetic sheath layer with high magnetic material content is used for sufficient shielding, then the electromagnetic shielding performance is improved, but the tensile strength and damage resistance of the metal foil deteriorate
Solution Approach 1:
The patent applies local quality by creating a non-uniform distribution of magnetic powder particles within the magnetic sheath layer. Fine particles (1-10 μm) are distributed to fill gaps and provide uniform shielding, while coarse particles (10-100 μm) are distributed to provide structural framework. This local differentiation allows sufficient shielding performance without excessive overall magnetic material content, preserving metal foil strength.
Solution Approach 2:
The magnetic sheath layer has a porous or particulate composite structure where magnetic powder particles are dispersed in the polymer matrix with interstitial spaces. This porous structure reduces the overall density and stiffness of the magnetic sheath layer, allowing it to be more compliant and less likely to damage the metal foil during bending, while still maintaining electromagnetic shielding through the distributed magnetic particles.
3Object-affected harmful factors
If a ferrite core is mounted on the outer periphery for reducing electromagnetic wave interference, then the shielding performance is improved, but the cable weight and space requirements increase remarkably
Solution Approach 1:
The patent extracts the essential shielding function from the traditional ferrite core concept and implements it as a thin magnetic sheath layer containing magnetic powder particles. This extracted approach provides the necessary electromagnetic shielding without the excessive weight and bulk of a solid ferrite core, as only a small amount of magnetic powder dispersed in the polymer matrix is needed to achieve effective shielding.
Solution Approach 2:
The patent uses a thin magnetic sheath layer (a flexible shell structure) containing magnetic powder particles instead of a thick ferrite core. This thin film approach provides electromagnetic shielding while maintaining cable flexibility and minimizing weight, as the magnetic effect is achieved through the distributed particles in the thin polymer matrix rather than a thick solid magnetic material.
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 cable maintains high electromagnetic shielding performance while preventing metal foil damage during bending and high-temperature exposure, ensuring reliable communication in flexible and high-temperature environments.
Implementation Method 1
a member containing a magnetic material such as the one called a ferrite core may be mounted on the outer periphery of the coaxial cable
Implementation Method 2
a shield body made of a metal material such as a metal foil or metal braided wire and further providing a sheath layer containing a magnetic material outside the shield body
Data Source
AI summary
A communication cable 1 is provided with a conductor 2, an insulation layer 3 containing an organic polymer and covering an outer periphery of the conductor 2, a metal foil 5 for covering an outer periphery of the insulation layer 3, and a magnetic sheath layer 7 containing an organic polymer and a powdered magnetic material and covering an outer periphery of the metal foil 5. A tensile modulus of elasticity of the magnetic sheath layer 7 is lower than that of the insulation layer 3. Assuming that an organic polymer having a melting point of 100° C. or lower is a low melting point polymer and a mass ratio of the low melting point polymer to organic polymer components constituting each layer is a low melting point component ratio, the low melting point component ratio is larger in the magnetic sheath layer 7 than in the insulation layer 3.