PCB Coaxial Ground Shielding for High-Speed Signal Vias
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Solution Overview
Problem
Existing PCBs face issues with signal degradation due to crosstalk, particularly at high data transmission rates, as conventional ground vias do not provide sufficient shielding, limiting signal integrity and data transfer rates.
Innovation Solution
Implementing coaxial ground shields around signal vias, which are substantially surrounded by a ground via plated with metal and filled with resin, providing enhanced electromagnetic shielding and reducing crosstalk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ground vias are used for shielding, then device complexity is reduced, but signal integrity deteriorates due to insufficient electromagnetic shielding at high data transmission rates
Solution Approach 1:
The patent implements a nested shielding structure where an inner ground via is positioned inside an outer ground via, creating a coaxial arrangement. This nested configuration enhances electromagnetic shielding effectiveness by providing multiple concentric shielding layers around the signal via, thereby improving signal integrity at high data transmission rates while maintaining a compact design.
Solution Approach 2:
The patent employs a composite shielding structure combining multiple conductive materials (inner ground via material, outer ground via material, and signal via material) with different electrical and electromagnetic properties. This composite approach optimizes shielding effectiveness across different frequency ranges and electromagnetic interference types, improving signal integrity without requiring excessive complexity in any single material layer.
2Object-affected harmful factors
If coaxial ground shields with nested ground vias are implemented, then electromagnetic shielding is enhanced, but device complexity increases
Solution Approach 1:
The patent implements a nested shielding structure where an inner ground via is positioned inside an outer ground via, creating a coaxial arrangement. This nested configuration enhances electromagnetic shielding effectiveness by providing multiple concentric shielding layers around the signal via, thereby improving signal integrity at high data transmission rates while maintaining a compact design.
Solution Approach 2:
The patent applies enhanced shielding specifically around high-speed signal vias that are susceptible to crosstalk, rather than uniformly across all vias on the PCB. The nested ground via structure is strategically implemented at critical signal transmission points where crosstalk mitigation is most needed, optimizing the balance between crosstalk reduction and overall device complexity.
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
The coaxial ground shields improve signal integrity by reducing crosstalk, enabling higher data transfer rates up to 212 Gbps per differential pair or 45 Gbps per lane single-end signals, while maintaining cost-effectiveness.
Implementation Method 1
a coaxial ground shield that provides ground shielding for the signal via. The coaxial ground shield can include a slot extending from a bottom of the ground via. The inner walls of the ground via can be plated with metal
Data Source
AI summary
A device includes a printed circuit board (PCB) including a signal trace electrically coupled to a signal via. The device further includes a coaxial ground shield configured to reduce signal interference with respect to the signal via. The coaxial ground shield includes a ground via formed in the PCB substantially surrounding the signal via and substantially coaxial with the signal via. The coaxial ground shield further includes metal plating on a wall of the ground via. The metal plating is electrically coupled to a ground plane of the PCB. The coaxial ground shield further includes resin at least partially filling the ground via.