PCB Ground Electrode Layout for High-Frequency Signal Isolation
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Solution Overview
Problem
Highly integrated circuit boards face challenges in achieving sufficient isolation between signal lines due to insufficient suppression of excitation currents, which leads to reduced isolation efficiency.
Innovation Solution
The circuit board design incorporates a ground electrode with protruded and recessed areas along its outer edge, where via conductors are positioned to match the shape, increasing the current path length and allowing excitation currents to escape, thereby enhancing isolation between signal lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ground electrode is connected to via conductors to suppress excitation current propagation, then isolation between signal lines is improved, but the suppression effect is insufficient for highly integrated circuit boards
Solution Approach 1:
The ground electrode is divided into multiple isolated ground segments separated by recessed areas. This segmentation prevents excitation currents from flowing continuously along the ground electrode edge, as the recessed areas create gaps that interrupt the current path. Each ground segment is independently connected to via conductors, enhancing the suppression of excitation currents and improving signal line isolation in highly integrated circuit boards.
2Reliability
If via conductors are positioned to match protruded and recessed areas, then excitation current escape is enhanced, but manufacturing complexity increases
Solution Approach 1:
The protruded and recessed area pattern is formed on the ground electrode before positioning the via conductors. This preliminary formation of the ground electrode structure with its characteristic protrusions and recesses provides predetermined positioning features that guide the subsequent placement of via conductors. The via conductors are then positioned to align with these pre-formed features, ensuring accurate placement while simplifying the manufacturing process compared to positioning via conductors without such guiding structures.
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
This configuration effectively reduces excitation currents flowing in the ground electrode and between signal lines, resulting in improved isolation and reduced radiation noise.
Implementation Method 1
when a current I101 based on a high-frequency signal flows in the signal line 111, an excitation current I102 flows along the edge of the ground electrode 113
Implementation Method 2
The plurality of via conductors 114 are cylindrical interlayer conductors. Ends of the via conductors 114 are arranged along one side of the outer edge of the ground electrode 113 and connected to the ground electrode 113
Data Source
AI summary
To enhance the isolation between signal lines for transmitting high-frequency signals included in a circuit board. A circuit board includes a plurality of signal lines for transmitting high-frequency signals, a ground electrode positioned between the plurality of signal lines and spaced apart from each of the plurality of signal lines, and a plurality of via conductors connected to the ground electrode. When the circuit board is seen in plan view, the ground electrode has a protruded and recessed area in at least a section of an outer edge thereof, the protruded and recessed area outwardly protruded and inwardly recessed. The plurality of via conductors is positioned in the protruded and recessed area so as to match with a protruded and recessed shape of the protruded and recessed area.