Edge Plated PCB Ground Shielding for EMI Suppression
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Solution Overview
Problem
Electronic devices face challenges in containing electromagnetic interference (EMI) emissions, which can interfere with surrounding electronics, and existing solutions do not effectively manage EMI across the spectrum from kilohertz to gigahertz frequencies.
Innovation Solution
An edge plated printed circuit board (PCB) is designed with copper electroplating that extends inner ground layers to its edge, providing a direct electrical connection to external EMI suppression components like gaskets and chassis, enhancing ground shielding and reducing common mode impedance and noise coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional PCB designs are used with internal ground layers not extending to the edge, then manufacturing is simpler, but EMI emissions escape from the PCB edge and ground shielding is insufficient
Solution Approach 1:
The ground shielding is segmented into two parts: internal ground layers within the PCB multi-layer structure and an external ground strip on the PCB edge. The internal ground layers handle EMI containment within the PCB, while the external ground strip extends to the edge to provide continuous shielding and connect to external EMI suppression components, effectively blocking EMI emissions without requiring complete redesign of the entire PCB structure.
Solution Approach 2:
The ground shielding is extended from the internal two-dimensional plane of the PCB layers to the third dimension by adding an external ground strip that protrudes from the PCB edge. This dimensional extension creates a continuous ground path that blocks EMI emissions escaping from the edge while maintaining compatibility with the existing multi-layer PCB structure.
2Object-affected harmful factors
If copper strips and vias are used to connect ground layers to the edge, then EMI shielding is improved, but the number of components and manufacturing complexity increase
Solution Approach 1:
The external ground strip is merged with the PCB edge itself, forming an integrated structure where the ground shielding is part of the PCB substrate rather than a separate component. This merging eliminates the need for additional copper strips and vias to connect ground layers to the edge, as the ground strip is directly formed on the PCB edge during fabrication, simplifying the manufacturing process while maintaining effective EMI shielding.
3Area of stationary object
If ground strips are made thinner or eliminated, then PCB area is reduced, but electrical connection to external EMI shields may be insufficient
Solution Approach 1:
The external ground strip acts as an intermediary element that provides the electrical connection between the internal ground layers and external EMI shields. By extending the ground shielding to the PCB edge, the ground strip serves as a direct mediator that ensures reliable electrical connection to external EMI suppression components without requiring thick ground strips or multiple vias, thus maintaining connection reliability while minimizing PCB area usage.
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 edge plated PCB effectively blocks EMI emissions and provides a robust connection for improved EMI management, reducing radiated emissions and common mode impedance, while potentially reducing the size and number of copper strips and vias, thus enhancing overall EMI suppression.
Implementation Method 1
copper electroplating, so that copper ground strips disposed at the top and bottom surfaces of the PCB and the inner ground layers are all electrically coupled to the plated edge
Data Source
AI summary
An edge plated printed circuit board (PCB) improves radiated emission performance by enhancing ground shielding on the PCB and improving the physical and electrical connection between the PCB and external EMI suppression components including an EMI chassis and gaskets. Inner ground layers within a multi-layer PCB are configured to physically extend to an edge of the PCB, which is plated using copper electroplating, so that copper ground strips disposed at the top and bottom surfaces of the PCB and the inner ground layers are all electrically coupled to the plated edge. In some embodiments, the ground strips can be made thinner compared to conventional arrangements, or be eliminated altogether as a result of the direct connection between the edge plated PCB and external EMI shields.