Porous Metallized Cable Shielding for EMI Leakage Control
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Solution Overview
Problem
Existing electrical cables face challenges with radio-frequency interference (RFI) and electromagnetic interference (EMI) leakage due to gaps and looseness in braided wire meshes or metal foils, leading to signal distortion and inconsistencies in attenuation behavior, especially at high frequencies.
Innovation Solution
A porous polymer core with metallized metallic layers and internal metallic structures that provide an electrically conductive path, allowing for improved electrical shielding and reduced capacitive behavior, which can be applied using conventional dielectric tape wrapping equipment, reducing complexity and variations in the wrapping process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a braided wire mesh or metal foil is used for shielding, then electrical shielding is provided, but gaps and looseness cause RFI leakage and signal distortion
Solution Approach 1:
The patent employs a porous polymer core material that maintains structural integrity while allowing for controlled porosity. This porous structure enables the shielding to maintain continuous electrical contact without the gaps inherent in braided constructions, thereby providing effective RFI/EMI shielding while ensuring signal integrity through consistent attenuation characteristics.
Solution Approach 2:
The patent uses a composite structure combining polymer and metal materials. The polymer core provides structural stability and electrical conductivity, while metal layers or coatings enhance the shielding effectiveness. This composite approach eliminates the gaps found in traditional braided shields while maintaining or improving shielding performance and signal integrity.
2Object-affected harmful factors
If braided wire mesh is used for shielding, then electrical shielding is achieved, but gaps cause inconsistencies in attenuation behavior at high frequencies
Solution Approach 1:
The porous polymer core provides a consistent, uniform structure that ensures reliable electrical contact across the shielding layer. This consistent porosity structure eliminates the gaps and irregularities found in braided constructions, thereby achieving uniform attenuation behavior at high frequencies while maintaining effective EMI shielding.
Solution Approach 2:
The patent modifies the physical and electrical parameters of the shielding material by using a porous polymer core with controlled porosity and conductivity. This parameter change from traditional braided structures to a porous composite material ensures consistent electrical contact and uniform attenuation characteristics across different frequencies, particularly at high frequencies where gap effects are more pronounced.
3Ease of manufacture
If conventional braiding methods are used, then shielding structure is formed, but gaps and looseness reduce shielding effectiveness
Solution Approach 1:
The porous polymer core is manufactured using techniques such as phase separation, foaming, or additive manufacturing, which create a controlled porous structure. This structure maintains continuous electrical contact without requiring complex braiding operations, thereby eliminating RFI leakage paths while keeping the manufacturing process simple and efficient.
Solution Approach 2:
The composite structure of polymer and metal materials allows for simplified manufacturing compared to traditional braiding. The polymer core can be formed using conventional extrusion or molding techniques, and metal layers can be applied through deposition or lamination, eliminating the need for complex braiding operations while providing superior shielding effectiveness without gaps or looseness.
4Reliability
If metal foil or wire mesh is used for shielding, then electrical conductivity is provided, but complexity and variations in wrapping process increase
Solution Approach 1:
The porous polymer core integrates electrical conductivity and shielding functionality into a single material structure. The controlled porosity allows for consistent electrical contact without requiring multiple layers or complex wrapping patterns, thereby simplifying the manufacturing process while maintaining reliable electrical conductivity and shielding effectiveness.
Solution Approach 2:
The composite structure combines polymer and metal materials to provide both structural integrity and electrical conductivity in a single component. This eliminates the need for separate wrapping operations and multiple layers required in traditional shielding constructions, thereby reducing process complexity and variations while ensuring consistent electrical conductivity.
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 enhances signal propagation characteristics at high frequencies with reduced distortion and improved flexibility, while maintaining tensile strength and minimizing RFI and EMI leakage, even when the cables are bent or flexed.
Implementation Method 1
a metallic link extending through the pore from the first metallic layer to the second metallic layer such that the metallic link provides an electrically conductive path between the first and second metallic layers
Data Source
AI summary
A cable includes an inner conductor, a dielectric layer extending around the inner conductor, and a polymeric material extending around the dielectric layer. The polymeric material includes a polymer core comprising opposite first and second sides. The polymer core includes a pore that extends through the first and second sides of the polymer core such that the polymer core is porous. The polymeric material includes first and second metallic layers extending on the first and second sides, respectively, of the polymer core. The polymeric material includes a metallic link extending through the pore from the first metallic layer to the second metallic layer such that the metallic link provides an electrically conductive path between the first and second metallic layers.