Flexible High-Frequency Signal Line with Segmented Ground Conductors
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Solution Overview
Problem
Conventional high-frequency signal lines, such as those using coaxial cables, face challenges in compactness and flexibility, particularly in mobile devices where space is limited, and existing flexible signal lines with copper foil ground conductors are prone to breakage when bent due to deformation resistance.
Innovation Solution
A high-frequency signal line design featuring a tri-plate stripline structure with flexible insulator layers, where ground conductors are not opposed to the signal line in certain sections, allowing for increased width and reduced transmission loss, and additional ground conductors are strategically placed to maintain impedance and prevent radiation, enabling easier bending without breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ground conductors are made of copper foil resistant to deformation, then manufacturing precision is improved, but reliability deteriorates when bending is required
Solution Approach 1:
The signal line is divided into multiple sections with different ground conductor configurations. First sections have ground conductors on both sides for stable impedance, while second sections have only one side ground conductors to enable bending without breakage.
Solution Approach 2:
Different sections of the signal line have different structural characteristics. Sections requiring impedance stability maintain opposed ground conductors, while sections requiring flexibility use non-opposed ground conductors, optimizing both impedance control and bendability locally.
2Volume of moving object
If signal line thickness is reduced to fit compact spaces, then volume of moving object is improved, but strength deteriorates
Solution Approach 1:
The signal line is segmented into first sections with opposed ground conductors for strength and second sections with non-opposed ground conductors for flexibility, allowing thin construction without sacrificing overall durability.
Solution Approach 2:
The characteristic impedance is controlled by adjusting the width and position of ground conductors and signal lines rather than increasing thickness, enabling compact dimensions while maintaining electrical performance and mechanical strength.
3Manufacturing precision
If ground conductors are placed opposed to signal line in all sections, then electrical characteristics are improved, but ease of operation deteriorates when bending is needed
Solution Approach 1:
The signal line is divided into first sections with opposed ground conductors for stable impedance and second sections with non-opposed ground conductors for bending flexibility, allowing both electrical performance and mechanical flexibility.
Solution Approach 2:
Opposed ground conductors are provided only in sections where impedance stability is critical, while non-opposed ground conductors are used in sections where flexibility is needed, optimizing the balance between electrical characteristics and bendability locally.
Data Source
AI summary
A high-frequency signal line includes an element assembly including a plurality of flexible insulator layers, a linear signal line provided in or on the element assembly, a first ground conductor arranged in or on the element assembly so as to be opposed to the signal line not in a first section including a portion of the signal line but in a second section adjacent to the first section, and a second ground conductor provided along the signal line in the first section on the insulator layer on which the signal line is provided. The second ground conductor is not opposed at least in part to the first ground conductor in the first section.