Directional Coupler Non-Overlapping Lines Phase Shift
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Solution Overview
Problem
Existing directional couplers suffer from insufficient directivity due to stronger odd mode coupling compared to even mode, leading to inadequate signal isolation and output characteristics.
Innovation Solution
A directional coupler design featuring a laminate body with non-overlapping main and sub-lines, and a phase adjusting circuit (low-pass filter) that causes a phase shift in passing signals, optimizing electromagnetic and capacitive coupling to enhance directivity and transmission characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the main line and sub-line are arranged with planes opposed to each other to achieve high capacitive coupling, then coupling efficiency is improved, but directivity deteriorates due to stronger odd mode appearing
Solution Approach 1:
The patent transitions from a planar opposed arrangement to a three-dimensional non-overlapping configuration where the main line and sub-line are positioned at different heights and angles, eliminating direct opposition while maintaining coupling through spatial distribution
Solution Approach 2:
The patent employs asymmetric positioning of the main line and sub-line, where they are neither parallel nor opposed but arranged at different orientations and elevations, disrupting the symmetry that generates strong odd mode coupling
2Reliability
If electromagnetic coupling and capacitive coupling are both present in the directional coupler, then coupling efficiency is improved, but signal cancellation occurs reducing directivity
Solution Approach 1:
The patent introduces a vertical dimension to separate the main line and sub-line, allowing electromagnetic coupling through proximity while reducing capacitive coupling by eliminating direct opposition, thus preventing signal cancellation
Solution Approach 2:
The patent creates different coupling characteristics at different locations and orientations, with the main line and sub-line positioned to achieve optimal local electromagnetic interaction while minimizing capacitive effects that cause cancellation
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
The design achieves improved directivity and transmission characteristics by restricting odd mode generation and maintaining high coupling efficiency, reducing signal cancellation and increasing output signal integrity.
Implementation Method 1
a first sub-line connected to the third terminal, electromagnetically coupled with the main line, and disposed on the insulation layer
Implementation Method 2
a phase adjusting circuit connected between the first sub-line and the second sub-line and configured to cause a phase shift on a passing signal
Data Source
AI summary
A directional coupler for use in a predetermined frequency band includes a laminate body including a laminate of a plurality of insulation layers, a first terminal through a fourth terminal disposed on a surface of the laminate body, a main line connected between the first terminal and the second terminal and disposed on the insulation layer, a first sub-line connected to the third terminal, electromagnetically coupled with the main line, and disposed on the insulation layer, a second sub-line connected to the fourth terminal, electromagnetically coupled with the main line, and disposed on the second sub-line, and a phase adjusting circuit connected between the first sub-line and the second sub-line and configured to cause a phase shift on a passing signal. The main line, the first sub-line and the second sub-line do not overlap each other in a plan view from a direction of lamination.