Printed Wiring Board Ground Plane Cross-Talk Reduction
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Solution Overview
Problem
Existing printed wiring boards face challenges in reducing size due to the need for separate shield covers, which increase material and assembly costs and lead to cross-talk issues between signal electrodes.
Innovation Solution
A printed wiring board design featuring a pattern layer, insulating layer, and ground layer laminated in an upper-lower direction with vias connecting a common ground plane to ground patterns, allowing signal pads to be arranged without additional shielding members, thereby preventing cross-talk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a separate shield cover is attached to the board, then cross-talk between signal electrodes is prevented, but material cost and assembly cost increase
Solution Approach 1:
The patent merges the shielding function with the ground layer structure by forming a continuous ground plane that extends to the board edge and covers the exposed cable portion. This integration eliminates the need for separate shield covers while maintaining cross-talk prevention, directly resolving the contradiction between harmful factor prevention and device complexity reduction
Solution Approach 2:
The ground layer serves multiple functions simultaneously: it provides electrical grounding for signal reference, shields signal electrodes from electromagnetic interference, and prevents cross-talk between adjacent signals. This multi-functionality eliminates the need for dedicated shield covers, reducing both material and assembly costs while maintaining cross-talk prevention
2Object-affected harmful factors
If a separate shield cover is attached to the board, then cross-talk between signal electrodes is prevented, but the board is difficult to be reduced in size
Solution Approach 1:
The shielding function is merged into the ground layer structure, eliminating the need for additional shield cover components. This integration allows the board to be reduced in size as the continuous ground plane provides shielding without requiring extra space for separate shield covers
Solution Approach 2:
The patent utilizes the vertical dimension by extending the ground plane to the board edge and covering the exposed cable portion, providing shielding in three-dimensional space without increasing the board's planar footprint. This dimensional approach enables size reduction while maintaining cross-talk prevention
3Reliability
If a shield cover is attached to the board, then impedance matching is achieved, but a gap is formed between the board and shield cover
Solution Approach 1:
The ground layer is merged with the board structure and extends to the edge, eliminating gaps between separate components. This continuous ground plane provides impedance matching while avoiding the gap formation issue associated with attached shield covers
Solution Approach 2:
The ground plane is pre-formed as an integral part of the board structure before cable attachment, ensuring continuous impedance control from the board through the cable connection point without gaps. This preliminary integration prevents the gap formation that occurs with post-assembly shield cover attachment
Data Source
AI summary
A printed wiring board comprises a pattern layer, an insulating layer and a ground layer laminated in an upper-lower direction. The printed wiring board is formed with one or more vias. The insulating layer is provided between the pattern layer and the ground layer. The ground layer is formed with a ground pattern. The pattern layer is formed with one common ground plane and two or more pads. The pads are arranged in a lateral direction. The common ground plane is located forward of the pads in the front-rear direction. The vias include a first via that connects the common ground plane and the ground pattern with each other. The pads include one or more ground pads and one or more signal pads. The ground pads are connected with the common ground plane. The signal pads are unconnected with the common ground plane.