Multipair Cable Shielding Asymmetry to Reduce Crosstalk
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Solution Overview
Problem
Multipair differential signal transmission cables suffer from pair-to-pair crosstalk due to the transmission of electromagnetic energy, particularly common-mode components, which are not effectively shielded by conventional methods, leading to signal quality deterioration.
Innovation Solution
The cable design features bundled differential signal transmission cables with longitudinally lapped shielding tape conductors, where the overlapping portions face outward to prevent common-mode electric field spread between adjacent cables, and additional shielding with a braided wire and jacket to minimize electromagnetic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If shielding tape conductor is used to shield each pair, then electromagnetic shielding is provided, but common-mode current flows through the shielding tape conductor generating magnetic field and causing pair-to-pair crosstalk
Solution Approach 1:
The shielding structure is made asymmetric by positioning the overlapping portion of the lapped shielding tape to face outward rather than inward. This local differentiation causes common-mode currents to flow toward the outer surface instead of concentrating on the inner surface, directing electromagnetic energy away from adjacent cable pairs and reducing crosstalk.
Solution Approach 2:
The shielding tape conductor is designed with asymmetric overlapping configuration where the overlap faces outward. This asymmetry changes the current distribution pattern, causing common-mode currents to flow on the outer surface of the shielding tape, thereby redirecting electromagnetic energy away from neighboring pairs and eliminating the crosstalk problem.
2Object-affected harmful factors
If conventional shielding is used, then some electromagnetic protection is achieved, but common-mode electric field spreads widely causing signal quality deterioration
Solution Approach 1:
The shielding structure creates a localized difference in electromagnetic field distribution by positioning the overlapping portion outward. This causes the common-mode electric field to be directed toward the outer surface, creating an asymmetric field pattern that prevents widespread interference and maintains signal integrity in adjacent pairs.
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 configuration significantly reduces pair-to-pair crosstalk by directing common-mode electric fields and currents away from adjacent cables, maintaining signal quality without increasing cable thickness, and is suitable for high-speed transmission applications.
Implementation Method 1
The transmission of electromagnetic energy is induced mainly by a common-mode component of which electric field spreads widely
Implementation Method 2
a braided wire covering a periphery of the second shielding tape conductor
Data Source
AI summary
A multipair differential signal transmission cable includes a plurality of differential signal transmission cables being bundled and each including two signal conductors as a differential pair covered with an insulation and a first shielding tape conductor provided therearound. The first shielding tape conductor is longitudinally lapped so as to have an overlapping portion in a cable longitudinal direction. The plurality of differential signal transmission cables include at least one or more pairs of two adjacent differential signal transmission cables. The two adjacent differential signal transmission cables are arranged such that the overlapping portion of one of the two adjacent differential signal transmission cables does not face the other of the two adjacent differential signal transmission cables.