Directional Coupler Asymmetric Ground Positioning
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Solution Overview
Problem
Directional couplers in mobile communication devices face challenges in maintaining a flat coupling degree across varying frequencies, with increased frequency leading to enhanced electromagnetic field coupling and frequency-dependent coupling degree issues.
Innovation Solution
The directional coupler design includes specific configurations such as varying characteristic impedances and electromagnetic couplings between lines, with shorter distances between certain lines and a ground conductor, and the use of layered dielectric structures to optimize coupling and isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the distance between transmission lines and ground conductor is increased to reduce electromagnetic coupling, then coupling degree decreases, but isolation deteriorates
Solution Approach 1:
The patent applies local quality by creating different distance relationships between ground conductors and transmission lines at different locations. Specifically, the ground conductor is positioned closer to the first transmission line (main line) than to the second transmission line (coupled line), creating asymmetric coupling characteristics that simultaneously control both coupling degree and isolation performance
Solution Approach 2:
The ground conductor acts as an intermediary element that mediates the electromagnetic interaction between transmission lines. By strategically positioning the ground conductor at different distances from different transmission lines, it serves as a controlled mediator that enables independent optimization of coupling and isolation characteristics
2Productivity
If frequency is increased to improve device performance, then electromagnetic field coupling is enhanced, but coupling degree becomes frequency-dependent
Solution Approach 1:
The patent employs parameter changes by varying the physical distances between ground conductors and transmission lines to create a coupling mechanism that is less sensitive to frequency variations. The asymmetric ground conductor positioning creates a coupling structure where the coupling degree remains relatively stable across different operating frequencies
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 reduces frequency dependence of the coupling degree and improves isolation, achieving a more stable coupling performance across a broader frequency range.
Implementation Method 1
a fourth line electromagnetically coupled with the first line
Implementation Method 2
a fifth line electromagnetically coupled with the second line
Implementation Method 3
a sixth line electromagnetically coupled with the third line
Data Source
AI summary
A directional coupler includes: a main line electrically connected between input and output terminals and including a first line, a second line connecting the first line and the input terminal, and a third line connecting the first line and the output terminal; a sub line electrically connected between coupling and isolation terminals and including a fourth line electromagnetically coupled with the first line, a fifth line electromagnetically coupled with the second line, and a sixth line electromagnetically coupled with the third line, the fifth line connecting the fourth line and the coupling terminal, the sixth line connecting the fourth line and the isolation terminal, and a ground conductor, shortest distances between the ground conductor and the first and fourth lines being less than shortest distances between the second, third, fifth, and sixth lines and the ground conductor.