Loop-Wrapping Ground Layer Circuit Board for Signal Integrity
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Solution Overview
Problem
Conventional circuit boards face impedance mismatch and electromagnetic interference (EMI) shielding gaps in coaxial vias, leading to noise interference and compromised signal integrity, especially for high-frequency signals.
Innovation Solution
The circuit board structure incorporates a loop-wrapping ground layer, insulating structure, and conductive vias to create a signal transmitting structure with equivalent circuits connected in series, ensuring impedance matching and reducing noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If one or more insulating layers are added between inner and outer conductive layers in conventional coaxial vias, then insulation is achieved, but impedance mismatch and EMI shielding gaps occur, degrading signal integrity
Solution Approach 1:
An insulating structure is introduced as an intermediary component positioned between the loop-wrapping ground layer and the inner conductive layer within the coaxial via. This insulating structure serves as a mediator that maintains proper electromagnetic field distribution, prevents direct contact between conductive elements, and ensures impedance matching without requiring multiple separate insulating layers, thereby simplifying the overall structure while improving signal integrity
Solution Approach 2:
The grounding structure is segmented into a loop-wrapping ground layer that specifically surrounds the inner conductive layer, rather than using a continuous outer ground layer. This segmentation allows the ground layer to closely follow the signal path, maintaining consistent impedance and reducing EMI shielding gaps, while the insulating structure fills the space between the loop-wrapping ground layer and inner conductive layer to prevent direct contact
2Adaptability or versatility
If coaxial through-hole design is used with signal and ground paths on different planes, then routing flexibility is improved, but noise interference cannot be reduced and signal integrity deteriorates
Solution Approach 1:
The inner conductive layer is nested within the loop-wrapping ground layer, creating a coaxial configuration where the signal path is surrounded by the ground path. This nesting arrangement maintains tight coupling between signal and ground, reducing EMI shielding gaps and noise interference, while still allowing routing flexibility through the via structure. The insulating structure fills the space between these nested conductive layers to prevent direct contact
Data Source
AI summary
Provided is a circuit board structure including a substrate, a loop-wrapping ground layer, an insulating structure, a first build-up layer, a top wiring layer, a bottom wiring layer, a first conductive via, and a plurality of second conductive vias. The aforementioned structure defines a signal transmitting structure. An equivalent circuit of the signal transmitting structure at least includes a first equivalent circuit, a second equivalent circuit, a third equivalent circuit and a fourth equivalent circuit, which correspond to different uniform transmitting sections respectively. The first equivalent circuit, the second equivalent circuit, the third equivalent circuit and the fourth equivalent circuit are connected in series with each other according to an ABCD transmission matrix series connection principle.