Double-Rib Waveguide Coupler Using Antenna-Based Short-Length Coupling

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Solution Overview

Problem

Existing bidirectional microwave couplers with holes are inefficient in terms of length, as they require significant space for hole-based coupling, leading to increased size and reduced directivity compared to desired specifications.

Innovation Solution

A bidirectional microwave coupler design featuring two parallel waveguides with double ribs and mechanically connected faces via a metallic layer, incorporating antenna assemblies within a dielectric insert to enhance coupling efficiency and reduce length, utilizing a dielectric insert with shoulders for secure mounting and thermal exchange facilitation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If hole-based coupling is used in parallel waveguides, then coupling between waveguides is achieved, but the coupler length becomes excessive and directivity deteriorates

Engineering Contradiction:
ImprovedirectivityVSAvoidcoupler length
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The patent changes the coupling mechanism from hole-based to antenna-based, fundamentally altering the coupling parameter. The antenna assemblies with specific geometries (dipoles, monopoles, or patches) enable stronger coupling coefficients, allowing the same coupling effect to be achieved in a shorter length. This parameter change directly addresses the contradiction by improving directivity while reducing length.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical hole-based coupling system with an antenna-based electromagnetic coupling system. The antenna assemblies, consisting of radiating elements mounted in dielectric inserts, create more efficient electromagnetic field interaction between waveguides, achieving better directivity in a compact form factor.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If hole-based coupling is used, then coupling is achieved, but the coupler size becomes too large

Engineering Contradiction:
Improvecoupling efficiencyVSAvoidcoupler volume
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent changes the coupling parameter from hole diameter and spacing to antenna geometry and positioning. The antenna assemblies provide stronger and more localized coupling, reducing the overall volume required to achieve the same coupling efficiency. This allows compact coupler designs without sacrificing coupling performance.

Inventive Principle:
Principle #35Parameter changes

3Length of stationary object

If antenna assemblies are used instead of holes, then coupling strength increases and length is reduced, but device complexity increases

Engineering Contradiction:
Improvecoupler lengthVSAvoidstructural complexity
Core Design Contradiction:
Length of stationary objectVSDevice complexity

Solution Approach 1:

The patent segments the coupler into modular antenna assemblies, each consisting of a radiating element mounted in a dielectric insert. These standardized modules can be replicated and positioned at different locations along the waveguides, providing design flexibility while maintaining manufacturing simplicity. The segmentation principle resolves the complexity issue by creating reusable building blocks.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The antenna assemblies serve multiple functions: they provide coupling between waveguides, define the coupling coefficient through their geometry, and can be configured to achieve different coupling strengths. This multi-functionality reduces the need for additional components, offsetting the increased structural complexity with functional integration.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 design shortens the coupler length by 30% to 70% while maintaining high directivity, achieving greater than 17 dB in the 6 to 18 GHz band, and allows for stronger coupling between the main and coupled tracks, outperforming hole-based couplers in terms of directivity and size.

Implementation Method 1

comprising antenna assemblies connecting the respective interiors of solid non-rib portions of the two waveguides, an antenna assembly comprising an antenna fixedly mounted in a dielectric insert fixedly mounted in said metal layer

Methodology Applied
Scientific EffectElectromagnetic coupling: Electromagnetic Induction

Implementation Method 2

an antenna fixedly mounted in a dielectric insert fixedly mounted in said metal layer

Methodology Applied
Scientific EffectDielectric insulation: Dielectric

Data Source

PatentEP3900104B1Bidirectional hyperfrequency coupler comprising two parallel double-rib waveguides
Publication Date: 2024.02.21 THALES SA
  • EP3900104B1 patent drawingFigure 1~2
  • EP3900104B1 patent drawingFigure 3~4
  • EP3900104B1 patent drawingFigure 5

AI summary

Bidirectional hyperfrequency coupler comprising two parallel (VP, VC) double-rib (NVP, NVC) waveguides having two respective faces arranged facing one another and mechanically connected by a metal layer (CM), and comprising antenna assemblies (EA) connecting the respective interiors of solid portions outside the ribs of the two waveguides (VP, VC), an antenna assembly (EA) comprising an antenna (Ant) securely mounted in a dielectric insert (Ins) securely mounted in the metal layer (CM).