Shielded Cable Film Structure for Bend-Stable Impedance
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Solution Overview
Problem
Existing electrical cables struggle with mass-termination techniques, flexibility, and maintaining high-speed electrical properties, especially when subjected to bends, which can cause impedance discontinuities and poor electrical performance.
Innovation Solution
A shielded electrical cable design featuring conductor sets with insulated conductors, first and second shielding films with cover and pinched portions, and an adhesive layer bonding the shielding films in pinched portions, allowing for flexible bending without significant impedance variation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional shielded cables are used, then electrical shielding is provided, but the cables cannot be mass-terminated and have poor flexibility when bent
Solution Approach 1:
The cable structure is segmented into multiple conductor sets with individual insulation, allowing each conductor to be independently terminated while maintaining the overall cable integrity. This segmentation enables mass-termination techniques where multiple conductors can be connected simultaneously to contact elements.
Solution Approach 2:
The cable employs thin shielding films instead of rigid shielding structures, allowing the cable to be flexible and bendable while maintaining electromagnetic shielding effectiveness. The thin film structure can conform to bent shapes without cracking or losing shielding performance.
2Ease of operation
If cables are bent to improve routability, then flexibility is improved, but impedance discontinuities occur causing poor electrical performance
Solution Approach 1:
The cable design controls the bend radius parameter to be no more than 180 degrees over an inner radius of at most 2mm, which maintains the electrical properties during bending. This parameter control ensures that impedance variation remains within acceptable limits (no more than 2 percent) even when the cable is sharply bent.
Solution Approach 2:
The cable uses composite construction with conductor sets, insulation layers, and shielding films bonded together with adhesive layers. This composite structure maintains geometric stability during bending, preventing relative movement between layers that could cause impedance discontinuities.
3Strength
If traditional cable designs are used, then structural integrity is maintained, but they are not suitable for high-speed data transmission
Solution Approach 1:
The cable provides different properties in different locations: conductor sets have precise geometric arrangements for high-speed signal transmission, while shielding films provide electromagnetic protection. Each region of the cable is optimized for its specific function, enabling both high-speed performance and structural integrity.
4Object-affected harmful factors
If shielding films are added to provide electromagnetic protection, then shielding effectiveness is improved, but the cable becomes less flexible and harder to terminate
Solution Approach 1:
The shielding function is extracted as separate thin films that can be applied to the conductor sets without requiring a completely different cable construction. This allows the shielding to be added while maintaining the basic cable structure suitable for mass-termination and high-speed transmission.
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 electrical performance and flexibility, enabling sharp bends without substantial impedance changes, thus supporting high-speed data transmission and improved routability in constrained spaces.
Implementation Method 1
an adhesive layer bonding the shielding films to each other in the pinched portions
Data Source
AI summary
A shielded electrical cable includes conductor sets extending along a length of the cable and spaced apart from each other along a width of the cable. First and second shielding films are disposed on opposite sides of the cable and include cover portions and pinched portions arranged such that, in transverse cross section, the cover portions of the films in combination substantially surround each conductor set. An adhesive layer bonds the shielding films together in the pinched portions of the cable. A transverse bending of the cable at a cable location of no more than 180 degrees over an inner radius of at most 2 mm causes a cable impedance of the selected insulated conductor proximate the cable location to vary by no more than 2 percent from an initial cable impedance measured at the cable location in an unbent configuration.