Stacked Transmission Line Layout for Signal Isolation

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Solution Overview

Problem

Existing transmission lines using coplanar waveguide structures face issues with interference and coupling between signal lines, leading to potential signal interference.

Innovation Solution

The transmission line design includes an insulator layer with first and second conductor patterns arranged at different positions in the thickness direction, where the first counter electrode overlaps the first signal line but not the second, and the second counter electrode overlaps the second signal line but not the first, reducing interference and improving isolation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If coplanar waveguide structure with grounds on both sides is used, then signal transmission is enabled, but interference between signal lines occurs due to inadequate isolation or coupling

Engineering Contradiction:

Improvesignal integrityVSAvoidinterference between signal lines

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent transitions from a two-dimensional coplanar waveguide structure to a three-dimensional stacked structure where signal lines are arranged in different layers. The first signal line is positioned in a first layer while the second signal line is positioned in a second layer, with counter electrodes strategically placed to provide isolation. This vertical dimensionality change enables better electromagnetic field control and reduced interference between adjacent signal lines.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent introduces counter electrodes as intermediary elements between signal lines to control electromagnetic coupling. The counter electrodes are positioned to overlap with specific signal lines in the vertical direction, acting as mediators that enable or suppress coupling as needed. This intermediary structure provides precise control over signal isolation and coupling characteristics.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If floating electrodes are arranged above and/or below grounds and signal lines, then shielding is provided, but isolation or coupling may be generated causing interference

Engineering Contradiction:

Improveshielding performanceVSAvoidisolation between signal lines

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent applies local quality by positioning counter electrodes to overlap with specific signal lines rather than providing uniform shielding across all signal lines. The first counter electrode overlaps the first signal line while the second counter electrode overlaps the second signal line, creating localized electromagnetic coupling control. This selective positioning enables precise control over which signal lines are coupled or isolated from each other.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS12609431B2Transmission line and electronic device including the same

Publication Date: 2026.04.21 MURATA MFG CO LTD

AI summary

A transmission line includes an insulator including at least one insulator layer, and first and second conductor patterns located in or on the insulator layer and arranged at positions different from each other in a thickness direction of the insulator layer. The first conductor pattern includes a first signal line and a second signal line each extending along a signal transmission direction. The second conductor pattern includes a first counter electrode and a second counter electrode. The first counter electrode overlaps the first signal line but does not overlap the second signal line when viewed in the thickness direction. The second counter electrode overlaps the second signal line but does not overlap the first signal line when viewed in the thickness direction.