I/O Interface Element with Ground Plane Clearances for Cross-Talk Reduction
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Solution Overview
Problem
High-speed, high-density interconnection systems face significant cross-talk issues due to electromagnetic coupling, particularly at the transition interface between printed circuit boards and cables, which conventional designs fail to adequately address, especially at data rates exceeding 5 Gbps.
Innovation Solution
The implementation of a multilayer printed circuit board with clearances adjacent to the transition interface and narrow grounding strips, separated by a web, reduces cross-talk while maintaining impedance matching, thereby minimizing signal distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional cable assemblies use printed circuit boards with traces and pads for high-speed signal transmission, then data transmission capability is achieved, but cross-talk between adjacent signal lines increases significantly
Solution Approach 1:
The patent introduces a ground plane layer as an intermediary between adjacent differential signal pairs. This ground plane acts as a mediator that provides electromagnetic shielding and reference potential, reducing the harmful electromagnetic coupling between signal lines while allowing high-speed data transmission to continue.
Solution Approach 2:
The patent employs a composite structure combining signal traces, ground plane layers, and dielectric materials in a multilayer printed circuit board configuration. This composite construction creates controlled impedance environments and provides electromagnetic isolation, reducing cross-talk while maintaining signal integrity for high-speed transmission.
2Object-affected harmful factors
If ground plane layers are added within the printed circuit board to eliminate cross-talk between Rx and Tx lines, then cross-talk reduction is achieved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent segments the ground plane layer into specific regions positioned between differential pairs, rather than implementing a continuous ground plane throughout the entire board. This segmentation approach provides cross-talk reduction where needed while simplifying the overall structure and reducing manufacturing complexity in other areas.
3Reliability
If impedance compensation is used at the cable soldering interface to avoid signal reflection, then signal integrity is maintained, but cross-talk between signal lines increases
Solution Approach 1:
The patent applies different ground plane configurations to different regions of the printed circuit board. At the cable soldering interface, the ground plane is designed with specific local characteristics that maintain impedance compensation and signal integrity, while in other regions it provides cross-talk reduction. This localized optimization resolves the contradiction between signal integrity and cross-talk reduction.
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 achieves a 3 dB reduction in cross-talk between Tx and Rx pairs up to 5 GHz, enhancing electrical performance and compliance with 10 Gbps standards like IEEE 802.3ap 10GBASE-KR.
Implementation Method 1
it is known to insert a shielding into the connectors in the connection system in order to reduce the impact of cross-talk
Implementation Method 2
One differential signal is carried on two conductors, with the signal being represented as the difference in electrical levels between the conductors. A differential signal is more resistant to cross-talk than a single-ended signal, because any stray signals impinging on the conductors will generally change the level on both conductors, but do not alter the difference in levels.
Data Source
AI summary
The present invention relates to a high speed input/output (I/O) connection interface element, to a cable assembly comprising such an interface element and to an interconnection system comprising such a cable assembly and a belonging jack connector for contacting the cable assembly. The I/O connection interface element comprises a substrate (102) carrying a plurality of electrically conductive leads (106), each of said conductive leads having an I/O transition interface to be connected to at least one I/O conductor. The electrically conductive leads comprise input leads and output leads which are arranged on opposing faces of said substrate, and wherein at least one electrically conductive ground plane layer (116) is arranged at least partially within said substrate, being electrically insulated from said plurality of conductive leads. At least one ground plane layer is provided with at least one clearance (118) in a region adjacent to the transition interface.