Directional Waveguide Coupler for Beamforming Networks

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Solution Overview

Problem

Existing beamforming networks for overlapped subarray antennas are complex, heavy, and voluminous, with high production costs and complex assembly requirements, and fail to ensure isolation between linear polarizations.

Innovation Solution

A 4x4 directional waveguide coupler with dual linear polarization capabilities, comprising four parallel rectangular waveguides forming a 2x2 cross-section matrix, arranged in multiple layers with switching waveguides for simplified production and assembly, and featuring slot arrays for accurate alignment and reduced losses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If 4x4 cascade directional couplers are used in beamforming networks, then the coupling functionality is achieved, but the mass and volume of the network increase significantly

Engineering Contradiction:
Improvecoupling functionalityVSAvoidmass of beamforming network
Core Design Contradiction:
Adaptability or versatilityVSWeight of stationary object

Solution Approach 1:

The patent divides the complex 4x4 directional coupler into multiple 2x2 directional coupler modules arranged in a cascade configuration. Each 2x2 module handles a subset of the coupling operations, and by segmenting the overall function into these smaller modular units, the total mass and volume are reduced compared to implementing a single monolithic 4x4 coupler while maintaining the required coupling functionality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs a nested structure where 2x2 directional coupler modules are arranged in cascading stages, with each stage nested within the overall beamforming network architecture. This nesting allows efficient space utilization and reduces the overall volume required for the beamforming network while achieving the complex 4x4 coupling function through hierarchical composition of simpler modules.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Adaptability or versatility

If 4x4 cascade directional couplers are used in beamforming networks, then the coupling functionality is achieved, but the volume of the network increases

Engineering Contradiction:
Improvecoupling functionalityVSAvoidvolume of beamforming network
Core Design Contradiction:
Adaptability or versatilityVSVolume of stationary object

Solution Approach 1:

The patent segments the 4x4 directional coupler function into multiple 2x2 modules that can be compactly arranged in cascade. This segmentation enables a more space-efficient implementation by utilizing modular building blocks that occupy less volume than a monolithic implementation would require.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent arranges the 2x2 directional coupler modules in a three-dimensional cascade configuration, utilizing spatial arrangement in multiple dimensions to achieve the 4x4 coupling function. By transitioning from a planar to a volumetric arrangement, the network achieves the required functionality with reduced overall volume through efficient spatial packing of the modular components.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Adaptability or versatility

If conventional 4x4 directional couplers are used, then coupling is achieved, but production costs and assembly complexity increase

Engineering Contradiction:
Improvecoupling capabilityVSAvoidproduction cost and assembly simplicity
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent segments the complex 4x4 directional coupler into standard 2x2 directional coupler modules, which are more common and easier to manufacture. This segmentation allows for standardized production processes, reduced tooling costs, and simpler assembly procedures compared to manufacturing custom monolithic 4x4 couplers, thereby reducing overall production costs and assembly complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses multiple copies of the standardized 2x2 directional coupler module to build the 4x4 coupling function. By copying and assembling these standardized modules rather than manufacturing a unique complex component, the production cost is reduced through economies of scale and the assembly process is simplified through repetition of standard procedures.

Inventive Principle:
Principle #26Copying

4Adaptability or versatility

If conventional directional couplers are used, then coupling is achieved, but isolation between linear polarizations is not ensured

Engineering Contradiction:
Improvecoupling capabilityVSAvoidisolation between polarizations
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies specific structural modifications to the 2x2 directional coupler modules, particularly in the configuration of coupling slots and waveguide dimensions, to provide polarization isolation at local levels. By optimizing the local geometry of each module, the design ensures that electromagnetic fields of different linear polarizations remain isolated during coupling operations, thereby ensuring reliable polarization separation throughout the overall 4x4 coupler system.

Inventive Principle:
Principle #3Local quality

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 solution results in a significantly reduced mass and volume of beamforming networks while maintaining radiofrequency performance, with production costs and assembly complexity decreased by half, and ensuring isolation between linear polarizations.

Implementation Method 1

The waveguides W1, W2, W3, W4 are coupled to one another by means of slot arrays S1-S4

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3618178B1Directional waveguide coupler, beamforming network, and antenna array comprising said coupler
Publication Date: 2021.11.24 AIRBUS ITAL SPA
  • EP3618178B1 patent drawingFigure 1
  • EP3618178B1 patent drawingFigure 2
  • EP3618178B1 patent drawingFigure 3~4

AI summary

A directional waveguide coupler (20), having four input ports and four output ports, wherein each of the input ports is coupled to each of the output ports, wherein the directional coupler (20) comprises: - a first coupler having two waveguides (W1, W2) coupled to each other by means of a first slot array (S1), defined in a first wall (21) common to the two waveguides (W1, W2) of the first coupler; - a second coupler having two waveguides (W3, W4), coupled to each other by means of a second slot array (S2), defined in a second wall (22) common to the two waveguides (W3, W4) of the second coupler. The first slot array (S1) and the second slot array (S2) lie on a first common plane. The first and second couplers are coupled to each other by means of a third slot array (S3) and a fourth slot array (S4), which lie on a second common plane perpendicular to the first common plane.