High-Frequency Signal Line Positional Control
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Solution Overview
Problem
High-frequency signal lines with stripline structures face challenges in maintaining a predetermined positional relationship between the signal line and ground conductors during lamination, leading to deviations in capacitance and inductance, which affect the characteristic impedance and electrical characteristics.
Innovation Solution
A high-frequency signal line is designed with a laminate structure featuring a signal line between two ground conductors, where one ground conductor has openings overlapping the signal line, and the other is positioned opposed to it, with specific thickness ratios and configurations to maintain the desired positional relationship and impedance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If dielectric layers are laminated to form a flexible stripline, then the signal line can be accommodated in a small space, but the positional relationship between the signal line and ground conductors may deviate from the predetermined relationship
Solution Approach 1:
The ground conductors are formed on the dielectric layers before lamination, with their positions and shapes predetermined. This preliminary formation ensures that when the layers are laminated together, the ground conductors automatically align with the signal line at the correct positions, preventing any deviation in the positional relationship while maintaining the compact flexible structure
Solution Approach 2:
The dielectric layers serve as intermediaries that precisely position the ground conductors relative to the signal line. By forming ground conductors on these dielectric layers before assembly, the layers act as positioning fixtures that maintain the predetermined positional relationships during lamination, ensuring manufacturing precision while achieving compact space utilization
2Ease of operation
If openings are provided in the ground layer to improve flexibility, then the board can be bent readily, but misalignment during lamination causes deviation in the positional relationship
Solution Approach 1:
The openings in the ground layer are predetermined in position and shape before lamination. This preliminary configuration allows the ground layer to be formed with the exact pattern needed, ensuring that even with openings present, the ground conductors maintain their correct positional relationship with the signal line after lamination, thus preserving both flexibility and precision
Solution Approach 2:
The ground layer has different properties in different regions: areas with openings provide flexibility and bendability, while areas with ground conductors maintain electrical integrity and positional precision. This local differentiation allows the board to be bent readily in needed areas while maintaining accurate positional relationships where electrical connections are required
3Reliability
If the positional relationship between signal line and ground conductors deviates, then the characteristic impedance and electrical characteristics are affected, but maintaining precise positioning increases manufacturing complexity
Solution Approach 1:
The formation of ground conductors on dielectric layers is merged with the lamination process itself. By preparing ground conductors on dielectric layers in advance and then laminating, the positioning function and assembly function are combined into one step, ensuring precise characteristic impedance without requiring separate complex positioning operations
Solution Approach 2:
Ground conductors are preliminarily formed on dielectric layers with predetermined positions and shapes before the final assembly. This preliminary preparation ensures that when layers are laminated, the characteristic impedance is automatically maintained at the correct value, achieving reliable electrical characteristics while keeping the manufacturing process relatively simple
Data Source
AI summary
A high-frequency signal line includes a laminate of a plurality of insulator layers, a signal line provided on a first principal surface of one of the insulator layers, a first ground conductor provided on a second principal surface of the insulator layer provided with the signal line, the first ground conductor including openings that overlap with the signal conductor, and a second ground conductor provided in or on the laminate so as to be opposed to the first ground conductor with the signal conductor positioned therebetween.