Twinaxial Cable Insulator Geometry for Low Mode Conversion
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Solution Overview
Problem
Twinaxial cables with large distances between conductors suffer from unbalanced differential pairs, leading to high mode conversion and noise in high-speed differential signal transmission, which degrades system performance.
Innovation Solution
A cable design with arc-shaped insulators and deformation surfaces, where the distance between conductor central axes is optimized to S/D ≤ 0.99, reducing the gap between conductors and minimizing mode conversion through the use of an intermediate layer material and deformation surfaces to press insulators against each other.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the distance between twinaxial cables is large, then the manufacturing process is easier and conductors are less deformed, but the differential pair becomes unbalanced leading to higher mode conversion
Solution Approach 1:
The patent changes the geometric parameters of the insulators by introducing arc-shaped surfaces with specific radii of curvature. The first insulator has an arc-shaped surface with radius R1 and the second insulator has an arc-shaped surface with radius R2, where the ratio R1/R2 is controlled within 0.95-1.05. This parameter adjustment allows the insulators to deform and press against each other, reducing the distance between conductors from the standard configuration to achieve better differential pair balance and lower mode conversion
Solution Approach 2:
The patent applies curvature to the insulator surfaces by creating arc-shaped surfaces instead of flat or cylindrical surfaces. The first insulator includes an arc-shaped surface and the second insulator includes an arc-shaped surface, which when pressed together create a deformation that reduces the distance between the twinaxial cables. This curved geometry enables the insulators to conform to each other and maintain consistent spacing, improving differential pair balance while maintaining ease of manufacture
2Reliability
If the distance between conductors is reduced, then mode conversion is lowered and signal integrity is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent controls the arc radius parameters R1 and R2 within specific ranges to achieve the desired conductor spacing. By specifying that R1/R2 should be between 0.95-1.05 and controlling the absolute values of R1 and R2, the patent provides manufacturing tolerances that balance precision requirements with achievable production standards, reducing mode conversion without excessive precision demands
Solution Approach 2:
The intermediate layer material is introduced between the first and second insulators. This intermediate layer acts as a mediator that facilitates the pressing and deformation of the arc-shaped insulator surfaces against each other. The intermediate layer material enables the insulators to conform to each other's curvature, achieving consistent reduced spacing between conductors while accommodating normal manufacturing variations without requiring extreme precision
Data Source
AI summary
A cable includes a first metal conductor, a first insulator, a second metal conductor and a second insulator. The first insulator includes a first arc-shaped surface. The second insulator includes a second arc-shaped surface. A distance between a central axis of the first metal conductor and a central axis of the second metal conductor is S. The first insulator and/or the second insulator are formed with a deformation surface at a position where the first insulator and the second insulator are in contact with each other. An outer diameter of a circle where the first arc-shaped surface is located and/or an outer diameter of a circle where the second arc-shaped surface is located is D, where S/D≤0.99. The cable of the present disclosure can achieve low mode conversion and improve high frequency characteristics.