Offset Block Waveguide Coupler with Centered Slot

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Solution Overview

Problem

Current waveguide couplers for parallel-plate transmission lines are bulky, have limited bandwidth, and are difficult to realize in practical injection-molded structures, with grating-lobe related limitations and high costs.

Innovation Solution

A waveguide coupler with a centered continuous slot and stepped sections along its sidewalls, allowing for controlled coupling into a parallel-plate transmission line, providing superior excitation control, compactness, and broader bandwidth.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If direct open-ended waveguide-to-parallel-plate interfaces are used, then coupling is achieved, but the structure becomes bulky and requires separate corporate or traveling-wave feed for excitation

Engineering Contradiction:
Improvecoupling capabilityVSAvoidstructure size
Core Design Contradiction:
Ease of operationVSVolume of moving object

Solution Approach 1:

The patent combines the waveguide feed and parallel-plate transmission line into a single integrated structure where the waveguide directly transitions to the parallel-plate line through a shared broadwall interface. This eliminates the need for separate corporate or traveling-wave feed structures, reducing overall complexity and size while maintaining effective coupling.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The waveguide structure serves multiple functions simultaneously: it acts as both the feeding mechanism and the transmission line structure. The broadwall interface provides both mechanical support and electromagnetic coupling, eliminating the need for dedicated separate feed structures.

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

2Ease of operation

If indirect slot-coupled waveguide-to-parallel-plate interfaces are used, then coupling is achieved, but the structure is bulky and has limited bandwidth due to resonant properties

Engineering Contradiction:
Improvecoupling capabilityVSAvoidbandwidth
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent removes the resonant slot coupling mechanism from the design. Instead of using indirect slot-coupled interfaces with their inherent resonant properties that limit bandwidth, the invention uses a direct broadwall transition that supports broader frequency operation without resonant constraints.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of operation

If horn-feeds are used, then coupling is achieved, but the structure is bulky and has limits on excitation phase and amplitude control

Engineering Contradiction:
Improvecoupling capabilityVSAvoidstructure size
Core Design Contradiction:
Ease of operationVSVolume of moving object

Solution Approach 1:

The patent merges the horn feed functionality directly into the waveguide-to-parallel-plate transition structure. The broadwall interface itself provides the excitation mechanism, eliminating the need for separate bulky horn feed structures while maintaining control over excitation characteristics.

Inventive Principle:
Principle #5Merging (Combining)

4Ease of operation

If conventional waveguide couplers are used, then coupling is achieved, but manufacturing is difficult and tolerance sensitivity is high

Engineering Contradiction:
Improvecoupling capabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The patent segments the waveguide structure into distinct sections (input waveguide, transition section with stepped sections, and parallel-plate transmission line) that can be independently manufactured and then assembled. This modular approach simplifies manufacturing and reduces tolerance sensitivity compared to monolithic conventional couplers.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses stepped sections with varying dimensions along the waveguide to control the coupling characteristics. By changing geometric parameters (step heights, widths, and positions) rather than relying on precise positioning of multiple small features, the design achieves robust coupling that is less sensitive to manufacturing tolerances.

Inventive Principle:
Principle #35Parameter changes

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 enables efficient launching of uniform or non-uniform RF fields with enhanced design flexibility and tolerance insensitivity, suitable for millimeter wave frequencies, and simplifies the manufacturing process.

Implementation Method 1

controlled coupling of energy is performed via a centered continuous slot opening in a wall of the waveguide that connects one or both broadwall(s) of a rectangular waveguide to an adjoining parallel-plate transmission line

Methodology Applied
Scientific EffectElectromagnetic coupling: Electromagnetic Induction

Data Source

PatentEP3709435B1Offset block waveguide coupler
Publication Date: 2022.09.07 THINKOM SOLUTIONS INC
  • EP3709435B1 patent drawingFigure 1A~1B
  • EP3709435B1 patent drawingFigure 2
  • EP3709435B1 patent drawingFigure 3A~3B

AI summary

A waveguide coupler (10) includes a waveguide (14) having a first and a second port (20, 22), and a slot (18) formed in a broadwall (24) of the waveguide (14) between the first and second ports (20, 22), the slot (18) centered on the broadwall (24). A plurality of shifted waveguide sections (12) are arranged between the first and second ports (20, 22) and extend along a length of the waveguide (14). A parallel-plate transmission line structure (16) is coupled to the slot (18), wherein RF signals within one of the waveguide (14) or the parallel-plate transmission line structure (16) are communicated to the other of the waveguide (14) and the parallel-plate transmission line (16) through the slot (18).