Twinaxial Cable Shield Overlap Alignment for Signal Attenuation
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Solution Overview
Problem
Twinaxial cables used in high-speed data communications suffer from signal attenuation due to a bandstop effect caused by the overlapping shield wraps, which limits data communication frequencies and increases parasitic effects like jitter as the cable length increases.
Innovation Solution
The design includes a conductive shield wrapped around inner conductors with an overlap aligned with a low current plane, orthogonal to the inner conductors, which reduces the bandstop effect and allows for higher frequency transmission by filtering frequencies beyond the range needed for signal transmission, thereby minimizing signal attenuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the shield is wrapped around the conductors with overlapping wraps to reduce electrical noise and electromagnetic radiation, then the shielding effectiveness is improved, but a bandstop effect is created that attenuates signals at frequencies in a stopband
Solution Approach 1:
The patent applies local quality by creating a non-uniform shield structure where the overlap region is specifically positioned at the low current plane rather than being uniformly distributed. This localized modification at the overlap region reduces the bandstop effect while maintaining shielding effectiveness in other regions, thereby resolving the contradiction between noise reduction and signal transmission quality.
Solution Approach 2:
The patent changes the geometric parameter of the shield overlap by positioning it at the low current plane (orthogonal to the plane including the conductors) rather than parallel to the conductors. This parameter change in overlap positioning modifies the electromagnetic characteristics to reduce signal attenuation in the stopband while maintaining the shielding function.
2Length of stationary object
If the cable length is increased to extend transmission distance, then the data communication range is improved, but signal attenuation and parasitic effects like jitter increase due to the bandstop effect
Solution Approach 1:
By modifying only the local overlap region of the shield while maintaining the overall cable structure, the patent reduces signal attenuation along the entire cable length. This localized change at the overlap position allows longer cable lengths to be used without proportionally increasing signal loss and parasitic effects.
Solution Approach 2:
The patent changes the shield overlap positioning parameter to reduce the bandstop effect, which directly decreases signal attenuation. This parameter modification enables extended transmission distances by reducing the cumulative loss that would otherwise limit cable length.
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 enhances the center frequency of the bandstop filter, allowing for improved high-speed data communication by reducing signal loss and parasitic effects, particularly at frequencies above 5-10 GHz, thus extending the effective data transmission range without significant attenuation.
Implementation Method 1
the overlap creates an electromagnetic bandgap structure that acts as a bandstop filter, which attenuates signals at frequencies in a stopband
Implementation Method 2
The wraps of the shield create an overlap of the shield that forms an electromagnetic bandgap structure (EBG structure) that acts as the bandstop filter
Implementation Method 3
The shield, when wrapped around the conductors of a cable, acts as a Faraday cage to reduce electrical noise from affecting signals transmitted on the cable
Implementation Method 4
The shield also minimizes capacitively coupled noise from other electrical sources, such as nearby cables carrying electrical signals
Implementation Method 5
Due to skin effect, the current in the conductors to the load displaces on the outer surface of the conductor
Data Source
AI summary
A cable for high speed data communications is provided. The cable includes a first inner conductor enclosed by a first dielectric layer and a second inner conductor enclosed by a second dielectric layer. The first inner conductor is substantially parallel to the second inner conductor and to a longitudinal axis. The cable includes a conductive shield wrapped around the first and second inner conductors, with an overlap of the conductive shield along and about the longitudinal axis. The overlap is aligned with a low current plane. The low current plane is substantially parallel to the first and second inner conductors, substantially equidistant from the first and second inner conductors, and substantially orthogonal to a plane including the first and second inner conductors.