Asymmetric Shielded Cable Design for Skew Imbalance
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Solution Overview
Problem
Shielded electrical cables experience skew imbalance due to voids created by overlapping cable shields, affecting the differential signal transmission by changing the dielectric constant and leading to signal delay and skew issues.
Innovation Solution
The electrical cable design features conductors of different diameters and insulators to balance the skew effects by adjusting the inductance and capacitance, with the first conductor having a smaller diameter and increased inductance to compensate for the capacitance decrease caused by the void, ensuring balanced signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a cable shield is wrapped around the conductor assembly, then electromagnetic shielding is improved, but voids are created at the overlap region causing dielectric constant changes and skew imbalance
Solution Approach 1:
The patent applies asymmetry by making the first conductor have a different diameter than the second conductor. Specifically, the first conductor has a smaller diameter to compensate for the void effect, creating an asymmetric conductor configuration that balances the skew caused by the cable shield overlap void.
Solution Approach 2:
The patent changes physical parameters of the conductors, specifically the diameter of the first conductor, to adjust its inductance and capacitance values. This parameter modification compensates for the dielectric constant change caused by the void, thereby balancing the skew between the two conductors.
2Manufacturing precision
If conductor diameters are made different to balance skew, then signal delay balance is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by modifying only the first conductor's diameter while keeping the second conductor unchanged. This localized modification targets specifically the conductor affected by the void, adjusting its electrical characteristics to achieve skew balance without unnecessarily complicating the entire conductor assembly.
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
This design mitigates skew imbalance by maintaining similar delay across the cable, ensuring zero or near-zero skew and improved signal performance in high-speed data transmission applications.
Implementation Method 1
a void is created that is filled with air, which has a different dielectric constant than the material of the insulator and shifts the cable shield farther from the signal conductor
Implementation Method 2
the diameter difference between the first diameter and the second diameter creating an increase in inductance in the first conductor compared to the second conductor
Data Source
Figure 1~3
Figure 2
AI summary
An electrical cable (100) includes a conductor assembly (102) having a first conductor (110), a second conductor (112), a first insulator (114) surrounding the first conductor (110) and a second insulator (116) surrounding the second conductor (112). The first insulator (114) has a first thickness (224) between the first conductor (110) and an outer surface (222). The second insulator (116) has a second thickness (324) between the second conductor (112) and an outer surface (322). The first thickness (224) is greater than the second thickness (324). A cable shield (120) is wrapped around the conductor assembly (102) and engages the outer surface (222) of the first insulator (114) along a first segment (240) and engaging the outer surface (322) of the second insulator (116) along a second segment (340). The cable shield (120) has an inner edge (130) and a flap (134) covering the inner edge (130). The cable shield (120) forms a void (140) at the inner edge (130) located closer to the first conductor (110) than the second conductor (112).