Embedded PCB Shielding Cavity Design for EMI Reduction
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Solution Overview
Problem
Electromagnetic interference (EMI) occurs between embedded electronic components in printed circuit boards, affecting the driving characteristics of the components, as existing techniques fail to effectively shield electromagnetic waves.
Innovation Solution
A printed circuit board design featuring a cavity with a metal pattern including multiple shielding patterns, where the first and second shielding patterns form a double structure surrounding the electronic device, and a third shielding pattern covers the cavity's opened surfaces, connected to the ground pattern to form a shield can structure, thereby shielding electromagnetic waves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If electronic components are embedded in a board to make the device slimmer and lighter, then the device size and weight are reduced, but electromagnetic interference occurs between components
Solution Approach 1:
The shielding structure is divided into multiple segmented shielding patterns (first shielding pattern, second shielding pattern, third shielding pattern) that are disposed at different locations and orientations. Each shielding pattern segment shields specific directions of electromagnetic waves, and together they form a comprehensive shielding system that reduces EMI while maintaining a compact embedded structure.
Solution Approach 2:
The shielding patterns are nested within the embedded structure of the printed circuit board. The first shielding pattern is disposed on the inner wall of the cavity, the second shielding pattern covers and spaces apart from the first, and the third shielding pattern covers opened surfaces. This nested arrangement creates multiple layers of electromagnetic shielding within the compact embedded space, effectively reducing EMI without significantly increasing device size.
2Object-affected harmful factors
If multiple shielding patterns are added to reduce electromagnetic interference, then EMI protection is improved, but the device complexity increases
Solution Approach 1:
The shielding patterns are integrated with the existing printed circuit board structure and ground patterns. The metal pattern serves multiple functions: it provides electromagnetic shielding in multiple directions, connects to ground patterns for EMI grounding, and is formed using the same manufacturing processes as existing PCB metal layers. This multi-functionality reduces the need for separate shielding components, thereby limiting the increase in device complexity.
Solution Approach 2:
The shielding patterns are merged with the ground pattern system of the printed circuit board. The first, second, and third shielding patterns are all connected to ground patterns, creating a unified electromagnetic shielding and grounding system. This integration combines the shielding function with the existing ground reference structure, reducing the need for separate shielding components and simplifying the overall design.
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 solution effectively reduces electromagnetic interference between embedded electronic devices, enhancing the driving characteristics and performance of the components by creating a comprehensive shielding structure that covers all sides and surfaces of the electronic device.
Implementation Method 1
a metal pattern including a first shielding pattern disposed on an inner wall of the cavity and a second shielding pattern spaced apart from the first shielding pattern and covering the first shielding pattern, an electronic device positioned in the cavity and surrounded by the first shielding pattern and the second shielding pattern
Data Source
AI summary
A printed circuit board includes a first insulating layer having a cavity, a metal pattern including a first shielding pattern disposed on an inner wall of the cavity and a second shielding pattern spaced apart from the first shielding pattern and covering the first shielding pattern, an electronic device positioned in the cavity and surrounded by the first shielding pattern and the second shielding pattern, and a second insulating layer stacked on the first insulating layer and embedding the electronic device therein.