Compact Directional Coupler Layout With Overlapping Coupling Path
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Solution Overview
Problem
In designing directional couplers, achieving a compact layout while maintaining a sufficient coupling factor is challenging, particularly when the transmission path is shortened or has fewer turns, leading to reduced electromagnetic interaction and coupling factor.
Innovation Solution
The directional coupler incorporates a coupling path that at least partially overlaps with the main path, featuring windings with innermost and outermost sections, and includes passive components like resistors and capacitors to adjust the coupling factor and achieve impedance matching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the transmission path is shortened to achieve compact layout, then the area is reduced, but the coupling factor decreases due to reduced electromagnetic interaction
Solution Approach 1:
The coupling path is configured to overlap with the main path, with the coupling path positioned inside or nested within the spatial envelope of the main path. This nesting arrangement allows the coupling path to be contained within the area defined by the main path, achieving compact layout while maintaining sufficient overlapping area for electromagnetic coupling. The nested configuration enables the coupling path to interact electromagnetically with the main path without requiring additional external space.
Solution Approach 2:
The patent transitions from a traditional side-by-side two-dimensional arrangement to a three-dimensional overlapping configuration. By allowing the coupling path to overlap with the main path in the vertical or depth dimension, the design achieves compact footprint area while maintaining sufficient interaction area. This dimensional transition enables the coupling path to be positioned above, below, or within the plane of the main path, effectively utilizing spatial volume rather than just surface area.
2Device complexity
If the transmission path has fewer turns to simplify structure, then the device complexity is reduced, but the coupling factor is weakened due to reduced interaction length
Solution Approach 1:
The coupling path is nested within the main path's spatial envelope, allowing multiple overlapping sections to be contained within a compact area. This nesting enables sufficient interaction length without requiring multiple external turns, as the coupling path can overlap with different sections of the main path sequentially within the same footprint area.
Solution Approach 2:
By utilizing the vertical or depth dimension through overlapping paths, the design achieves sufficient interaction length without requiring multiple horizontal turns. The coupling path can extend in the vertical dimension or overlap at different heights, providing the necessary interaction length while maintaining a simple two-path structure without additional turns.
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 allows for a compact directional coupler with a desired coupling factor, lower insertion loss, and efficient use of layout area, even when the main path is a single straight path with a shorter length.
Implementation Method 1
a directional coupler is a passive device used to couple a portion of the electromagnetic power in a signal path to another path
Implementation Method 2
The coupling factor may be determined by the electromagnetic interaction between the two paths
Data Source
AI summary
A directional coupler includes a main path, a coupling path, a first port, and a second port. The main path is used to propagate a first RF signal. The coupling path at least partially overlaps with the main path. The coupling path includes a first end, a second end, and at least one winding routed between the first end and the second end. The first port is coupled to the first end of the coupling path. The second port is coupled to the second end of the coupling path. At least one of the first port and the second port is located inside the at least one winding.