PCB Power Layer Ground Element Spacing for EMI Reduction
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Solution Overview
Problem
High-frequency circuit boards in electronic products generate electromagnetic noise due to high-speed switching operations, which interferes with wireless communication functions.
Innovation Solution
A Printed Circuit Board (PCB) structure with a power layer surrounded by ground elements, where the distance between adjacent ground elements is less than 0.1 wavelength of a predetermined frequency, forming parasitic and interlayer capacitances to redirect electromagnetic noise radiation to the ground, thereby reducing leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If ground elements are placed close together to reduce electromagnetic noise radiation, then the electromagnetic shielding effectiveness is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The ground plane is segmented into multiple discrete ground elements arranged in a specific pattern around the power shape, rather than using a continuous ground plane. This segmentation allows for controlled parasitic capacitance distribution while maintaining manufacturing feasibility.
Solution Approach 2:
The invention optimizes the distance between adjacent ground elements to be less than 0.1 wavelength of the predetermined frequency, creating a specific geometric parameter that achieves effective electromagnetic shielding while remaining manufacturable with standard PCB tolerances.
2Object-affected harmful factors
If the distance between ground elements is reduced to less than 0.1 wavelength, then electromagnetic noise radiation is reduced, but the device complexity increases
Solution Approach 1:
Multiple ground elements are connected through conductive via elements to create an equipotential reference plane, simplifying the overall structure by providing a unified ground reference while maintaining the beneficial effects of segmented ground elements for noise reduction.
Solution Approach 2:
The ground elements are merged with ground layers through conductive via elements, combining the advantages of discrete ground elements (controlled parasitic capacitance) with continuous ground planes (low impedance reference) into a hybrid structure.
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
Significantly reduces electromagnetic noise radiation, improving the Signal-to-Noise Ratio (SNR) and communication quality by creating a Faraday cage effect, with the potential for low-cost implementation in various wireless communication devices.
Implementation Method 1
a parasitic capacitance is formed between the first power shape and each of the ground elements, such that electric lines of force of the electromagnetic noise radiation begin from the first power shape, extend through the parasitic capacitances, and finally reach the ground elements
Implementation Method 2
an interlayer capacitance is formed between the first power shape and each of the first ground layer and the second ground layer, such that electric lines of force of the electromagnetic noise radiation begin from the first power shape, extend through the interlayer capacitances, and finally reach the first ground layer or the second ground layer
Implementation Method 3
A distance between any adjacent two of the ground elements is shorter than 0.1 wavelength of a predetermined frequency, so as to reduce electromagnetic noise radiation at the predetermined frequency
Data Source
AI summary
A PCB (Printed Circuit Board) structure at least includes a power layer. The power layer includes a first power shape and a plurality of ground elements. The first power shape is surrounded by the ground elements. The distance between any two adjacent ground elements is shorter than 0.1 wavelength of a predetermined frequency, so as to reduce electromagnetic noise radiation at the predetermined frequency.