EBG Printed Circuit Board for EMI Noise Shielding
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Solution Overview
Problem
Existing solutions for electromagnetic interference (EMI) noise shielding in electronic products, particularly at the board edges, are inadequate as they either generate new radiation noise due to antenna effects or have limitations in frequency absorption, leading to increased weight and production costs.
Innovation Solution
A printed circuit board design incorporating a second board with an Electromagnetic Band Gap (EBG) structure that is grounded to a shield can, providing effective noise shielding without antenna effects and across various frequencies, while being cost-effective and easy to apply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a shield can is used to shield EMI noise, then noise shielding is improved, but new radiation noise is generated due to antenna effect and weight increases
Solution Approach 1:
The patent extracts the harmful antenna effect from the shield can by introducing an EBG structure that selectively blocks only the noise frequencies while allowing other frequencies to pass through, thereby eliminating the unwanted radiation noise generation
Solution Approach 2:
The patent uses a composite structure combining the shield can with an EBG pattern layer formed on its inner surface, creating a hybrid shielding solution that leverages both the physical barrier properties of the shield can and the frequency-selective properties of the EBG structure
2Object-affected harmful factors
If an EMI field absorber is used to absorb EMI noise, then noise absorption is improved, but frequency range limitations and development time increase
Solution Approach 1:
The patent changes the fundamental parameter of noise control from absorption to reflection using the EBG structure, which blocks noise through constructive interference and standing wave formation rather than material absorption, thereby achieving broad frequency coverage without material development limitations
Solution Approach 2:
The EBG structure provides universal noise shielding across multiple frequency ranges by utilizing electromagnetic wave interference principles that are effective across a broad spectrum, eliminating the need for frequency-specific material development
3Object-affected harmful factors
If a shield can is used for noise shielding, then EMI protection is improved, but device weight and thickness increase
Solution Approach 1:
The patent replaces the thick, rigid shield can with a thin EBG pattern layer that can be formed directly on the inner surface of the shield can or even on the PCB surface, dramatically reducing the overall thickness and weight while maintaining shielding effectiveness
Solution Approach 2:
The patent substitutes the mechanical mass-based shielding approach (thick shield can) with an electromagnetic field-based approach (EBG structure) that achieves shielding through wave interference rather than physical barrier mass, thereby reducing weight
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 EBG structure effectively shields EMI noise across multiple frequencies without the antenna effect, offering better noise shielding than conventional methods while reducing production costs and weight, making it suitable for lightweight electronic devices.
Implementation Method 1
an Electromagnetic Band Gap (EBG) structure is inserted into the second board such that a noise radiating upwards from the first board is shielded
Data Source
AI summary
An electronic product includes a case; a first board placed inside the case; and a second board having an Electromagnetic Band Gap (EBG) structure inserted therein. The second board is coupled to an inside of the case facing the first board so as to shield a noise radiated from the first board.