Inter-layer Coupler with U-shaped Trace for 5G Pre-distortion
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Solution Overview
Problem
Current telecommunications system couplers are large, costly, and inefficient, requiring significant space due to their discrete or multi-layer designs, which hinders the miniaturization and cost reduction needed for advanced 4G to 5G systems, especially as power amplifiers operate near saturation, causing signal distortion that necessitates digital pre-distortion.
Innovation Solution
A high directivity compact size inter-layer coupler is designed with a main signal line on a top dielectric layer and a coupled line on an inner layer, featuring a U-shaped configuration with narrow line portions between blocks to enhance directivity and impedance matching, allowing efficient signal coupling for pre-distortion feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If discrete components or multi-layer designs are used for couplers, then coupling functionality is achieved, but device size and cost increase
Solution Approach 1:
The patent merges the coupling functionality directly into the PCB trace structure by forming the coupled line as an integrated part of the signal transmission path on the same substrate, eliminating the need for discrete coupler components and reducing overall device size while maintaining coupling functionality
Solution Approach 2:
The patent transitions from planar coupling designs to three-dimensional inter-layer coupling by routing the main signal line on one PCB layer and the coupled line on an adjacent layer, utilizing the vertical dimension to achieve compact coupling structure with reduced footprint
2Reliability
If discrete components or traditional multi-layer designs are used for couplers, then coupling functionality is achieved, but manufacturing cost increases
Solution Approach 1:
The patent combines the coupler functionality with the standard PCB manufacturing process by forming both main and coupled lines as integrated trace structures on the PCB substrate, eliminating the need for separate discrete components and reducing assembly steps, thereby lowering manufacturing cost
Solution Approach 2:
The PCB substrate serves multiple functions simultaneously as both the mechanical support structure and the signal transmission medium for both main and coupled lines, reducing the need for additional specialized components and simplifying the manufacturing process
3Reliability
If conventional coupler designs are used, then signal coupling is achieved, but directivity is insufficient
Solution Approach 1:
The patent implements varying trace widths along the coupled line, with narrower sections positioned strategically to optimize electromagnetic coupling at specific locations, thereby enhancing directivity through localized impedance control and selective coupling strength
Solution Approach 2:
The patent modifies the geometric parameters of the coupled line, including trace width, spacing from the main line, and length of coupling sections, to optimize the coupling coefficient and directivity performance, achieving precise control over signal extraction characteristics
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 compact coupler effectively reduces size and cost while improving directivity and impedance matching, ensuring minimal signal distortion by efficiently coupling feedback signals for pre-distortion, thus supporting high-performance telecommunications systems.
Implementation Method 1
a coupling line formed between the second and third dielectric layers, where the coupling line is electromagnetically coupled to the main line so as to generate the coupling signal thereon
Data Source
AI summary
A high directivity compact size inter-layer coupler that has application for coupling off a pre-distortion coupling signal from a main signal at an output of a power amplifier to a pre-distortion circuit. The coupler includes a main signal line formed on a surface of a first dielectric layer opposite to a second dielectric layer, where the main signal line receives the main signal, and a coupling line formed between the second dielectric layer and a third dielectric layer, where the coupling line is electromagnetically coupled to the main line so as to generate the coupling signal thereon. The coupling line has a general U-shape including a first leg portion, a second leg portion and a transverse portion between the first and second leg portions. The transverse portion includes a plurality of spaced apart blocks coupled together by a narrow line portion.