Interdigitated Directional Coupler Layout for High Directivity

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Solution Overview

Problem

Conventional directional couplers are lengthy, resulting in high insertion loss and occupying significant chip area, which limits their directivity and accuracy in power detection, especially for 5G cellular handset transmitters with degraded antenna VSWR.

Innovation Solution

A passive structure for compact directional couplers is designed, featuring a split structure for the coupled transmission lines with bridges connecting the sections, allowing for independent adjustment of coupled line parameters to achieve higher directivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of moving object

If conventional coupler structure is used, then coupling function is achieved, but length is long and chip area is large

Engineering Contradiction:

Improvechip areaVSAvoidcoupler length

Core Design Contradiction:

Area of moving objectVSLength of moving object

Solution Approach 1:

The second transmission line is divided into two separate sections (first section and second section) that are positioned on opposite sides of the first transmission line. This segmentation allows the coupled lines to be distributed more compactly across the chip, reducing the overall length and area occupied by the coupler while maintaining the required coupling function.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent transitions from a conventional linear arrangement of coupled lines to a spatial distribution where the second line's sections are positioned on opposite sides of the first line. This dimensional reconfiguration reduces the linear length requirement while achieving the same coupling effect in a more compact footprint.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Loss of energy

If conventional coupler structure is used, then coupling function is achieved, but insertion loss is high

Engineering Contradiction:

Improveinsertion lossVSAvoidcoupler length

Core Design Contradiction:

Loss of energyVSLength of moving object

Solution Approach 1:

By segmenting the second transmission line into two sections positioned on opposite sides, the signal path length is effectively reduced. This segmentation allows for a more direct signal transmission path between input and output ports, minimizing propagation losses and reducing overall insertion loss.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces adjustable coupling coefficients for the two sections, allowing dynamic optimization of the coupling parameters. This enables the system to be tuned for minimal insertion loss while maintaining the required directivity and coupling ratio, adapting to different operating conditions.

Inventive Principle:

Principle #15Dynamics

3Measurement precision

If conventional coupler structure is used, then basic coupling is achieved, but directivity is insufficient

Engineering Contradiction:

ImprovedirectivityVSAvoidcoupler structure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The second transmission line is segmented into two independently controllable sections, each with its own coupling coefficient. This segmentation provides an additional degree of freedom in the design, allowing independent optimization of directivity by adjusting the relative coupling strengths of the two sections without requiring a more complex overall structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the coupling parameters by introducing two distinct coupling coefficients (k1 and k2) for the two sections. By independently adjusting these parameters, the directivity can be optimized to achieve higher measurement precision while maintaining a relatively simple coupled-line structure.

Inventive Principle:

Principle #35Parameter changes

4Area of moving object

If coupler length is reduced, then chip area is reduced, but directivity deteriorates

Engineering Contradiction:

Improvechip areaVSAvoiddirectivity

Core Design Contradiction:

Area of moving objectVSMeasurement precision

Solution Approach 1:

Segmenting the second transmission line allows the coupler to achieve the required directivity in a shorter overall length. The two sections can be positioned closer together and configured with appropriate coupling coefficients to maintain directivity performance while reducing the total length and chip area occupancy.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

By introducing adjustable coupling coefficients for each section, the system can dynamically optimize the directivity performance even with reduced physical length. This dynamic parameter adjustment compensates for the shortened interaction length between coupled lines, maintaining high directivity in a compact structure.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS12206154B2Compact high-directivity directional coupler structure using interdigitated coupled lines

Publication Date: 2025.01.21 SAMSUNG ELECTRONICS CO LTD

AI summary

Disclosed is a device including a first line, a second line including a first section disposed on a first side of the first line and a second section disposed on a second side of the first line, the second side being opposite to the first side and the second section being separate from the first section by a distance, and at least one bridge electrically connecting an end of the first section with an end of the second section and extending across the first line. The device may be a directional coupler that achieves significantly higher directivity than conventional directional coupler structures, and hence, improves power detection accuracy.