High-Frequency Line Bend Structure for Impedance Matching
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Solution Overview
Problem
High-frequency line connecting structures face challenges in maintaining characteristic impedance matching and preventing signal reflection when connecting lines with different extension directions, particularly in high-density and three-dimensional wiring configurations, where traditional methods like chamfering are limited by manufacturing constraints and may lead to impedance mismatch and signal loss.
Innovation Solution
A high-frequency line connecting structure is designed with a connecting part that forms a space only on the outer peripheral side or both inner and outer peripheral sides, where the total volume of the space on the inner peripheral side is smaller than on the outer peripheral side, allowing for capacitive and inductive adjustments to maintain impedance matching and prevent signal reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chamfering is applied to the bent part of the high-frequency line, then impedance matching is improved, but the manufacturing precision deteriorates when the insulating layer thickness is reduced to several μm
Solution Approach 1:
The patent changes the geometric parameters of the bent part by introducing a curved section with a specific radius of curvature instead of a sharp right-angle bend. This curved configuration allows impedance matching without requiring precise chamfering, thereby maintaining manufacturing feasibility even when the insulating layer thickness is reduced to several μm.
Solution Approach 2:
The patent employs asymmetric positioning of via holes at the bent part, where the via hole on the outer peripheral side is positioned differently from the via hole on the inner peripheral side. This asymmetric arrangement compensates for impedance variations caused by the bend while avoiding the need for precise symmetric chamfering, thus resolving the contradiction between impedance matching and manufacturing precision.
2Adaptability or versatility
If the high-frequency line is bent at right angles to connect different directions, then wiring design freedom is improved, but characteristic impedance matching deteriorates
Solution Approach 1:
The patent replaces the right-angle bent configuration with a curved bent part having a specific radius of curvature. This curved geometry maintains the ability to connect high-frequency lines in different directions (preserving wiring design freedom) while smoothly transitioning the signal path to minimize impedance discontinuities (improving characteristic impedance matching).
Solution Approach 2:
The patent introduces via holes as intermediary elements at the bent part, with asymmetric positioning to mediate the impedance transition. These via holes act as impedance transformation elements that bridge the impedance difference between the straight and bent sections, enabling both directional connectivity and impedance matching.
3Quantity of substance
If the insulating layer thickness is reduced for high-density wiring, then wiring density is improved, but the ability to form chamfered structures deteriorates
Solution Approach 1:
The patent changes the bend geometry from a chamfered configuration to a curved configuration with a specific radius of curvature. This parameter change eliminates the need for chamfering processing, making the structure manufacturable even when the insulating layer thickness is reduced to several μm for high-density wiring applications.
Solution Approach 2:
The patent extracts the chamfering requirement from the design, replacing it with a curved bent part that achieves impedance matching through geometry alone. This extraction of the chamfering step simplifies the manufacturing process and enables implementation in thin insulating layers where chamfering would be difficult or impossible.
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 ensures smooth transmission of high-frequency signals without reflection by effectively matching characteristic impedance across the connecting part, even in complex three-dimensional configurations, thereby addressing the limitations of traditional methods in high-density and high-frequency applications.
Implementation Method 1
a space from which the substrate is removed is formed only on an outer peripheral side of the connecting part or on both an inner peripheral side and the outer peripheral side of the connecting part
Implementation Method 2
allowing for capacitive and inductive adjustments to maintain impedance matching
Data Source
AI summary
A high-frequency line connecting structure includes microstrip lines, and a connecting part which bends an extension direction of the line at a place where the microstrip lines are connected. Spaces from which the substrate is removed are formed on the inner peripheral side and the outer peripheral side of the connecting part. The total volume of the space on the inner peripheral side is smaller than the total volume of the space on the outer peripheral side.