Flat Cable EMI Suppression via Alternating Ground-Analog Shielding
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Solution Overview
Problem
Existing multiple-conductor flat cables face challenges in effectively suppressing electromagnetic interference (EMI) due to limitations in pathway flexibility, increased cost from additional components, and impedance issues when bent, especially when applied to electronic equipment with multiple cables.
Innovation Solution
A multiple-conductor flat cable design where ground and analog signal lines are alternately arranged and electrically insulated, with digital signal lines similarly arranged and insulated, allowing the analog cable portion to function as a shield for the digital cable portion, either rolled up or folded to absorb EMI without increasing impedance or requiring additional components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the flat cable is arranged along a conductive member connected to GND, then EMI radiation is suppressed, but the pathway of the flat cable is limited
Solution Approach 1:
The patent merges the EMI suppression function with the cable structure itself by integrating ground signal lines directly into the flat cable. The ground signal lines are formed integrally with the insulating layer and conductor layers, eliminating the need for separate conductive members or GND connections. This allows the cable to suppress EMI while maintaining pathway flexibility.
Solution Approach 2:
The patent extracts the EMI suppression function from the external conductive member and GND system and incorporates it directly into the cable structure. The ground signal lines are built into the cable layers, removing the dependency on external GND connections and enabling flexible cable routing.
2Object-affected harmful factors
If a spiral partition wall is added as a guide, then EMI radiation from signal lines is suppressed, but manufacturing cost increases
Solution Approach 1:
The patent merges the EMI suppression function with the existing cable structure by utilizing the insulating layer and conductor layers that are already part of the cable. The ground signal lines are formed using the same lamination process as the signal lines, eliminating the need for separate partition walls and reducing manufacturing cost.
Solution Approach 2:
The patent uses the existing insulating layer and conductor layers as the EMI suppression mechanism rather than adding expensive separate components. The ground signal lines are formed using standard PCB lamination techniques, making the solution cost-effective.
3Object-affected harmful factors
If the flat cable is bent or curled to avoid linear arrangement, then EMI radiation is suppressed, but the cable length increases and impedance increases
Solution Approach 1:
The patent merges the EMI suppression function with the cable structure by integrating ground signal lines alternately arranged with analog signal lines. This configuration provides continuous EMI suppression along the cable length without requiring bending or curling, maintaining both low impedance and effective noise suppression.
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 design effectively suppresses EMI by approximately −5 decibels, allows flexible placement without pathway restrictions, and reduces costs by eliminating the need for additional components or bending, which would increase impedance.
Implementation Method 1
an analog cable portion and a digital cable portion are placed adjacent to each other... the analog cable portion to function as a shield for the digital cable portion... to absorb EMI
Data Source
AI summary
A multiple-conductor flat cable includes: an analog cable portion formed such that ground signal lines and analog signal lines are alternately arranged side by side across a signal transmission direction and each adjacent pair of the ground signal lines and the analog signal lines are joined while being electrically insulated from each other; and a digital cable portion joined with the analog cable portion while being placed adjacent to the digital cable portion and formed such that digital signal lines are arranged side by side across the signal transmission direction and each adjacent pair of the digital signal lines are joined while being electrically insulated from each other.