Waveguide Rotator with Ridge for Compact Polarization Rotation

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Solution Overview

Problem

Existing rotator devices for connecting non-aligned waveguides are not compact enough and require complex machining processes, leading to increased costs and dimensions that exceed permitted tolerances.

Innovation Solution

A compact rotator device is designed by allowing the two angled sections of the waveguide to overlap, with a ridge protruding into the rotator portion, which lowers the cut-off frequency of the dominant mode and raises the cut-off frequency of the next higher order mode, allowing for rotation within a single section rather than between sections, and can be machined in a single piece using a two-step process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional step twists or bow-tie steps are used to connect non-aligned waveguides, then polarization rotation is achieved, but the device size increases and machining complexity increases

Engineering Contradiction:
Improvepolarization rotation performanceVSAvoiddevice size
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent implements nesting by allowing the two angled sections of the waveguide to overlap in space, with one section partially containing the other. This overlapping configuration enables the rotator to achieve the required polarization rotation within a compact volume, reducing the overall device size by 28% compared to traditional step-twist designs while maintaining effective broadband performance.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent transitions from a linear sequential arrangement of waveguide sections to a three-dimensional overlapping configuration. By utilizing spatial overlap and introducing a ridge structure that protrudes into the rotator portion, the design achieves polarization rotation in a more compact volume by exploiting the third dimension rather than simply extending the device length.

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

2Reliability

If multiple step twists or bow-tie steps are used to achieve high broadband performance, then polarization rotation is improved, but manufacturing cost increases and device complexity increases

Engineering Contradiction:
Improvebroadband performanceVSAvoidnumber of parts
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple waveguide sections into a single monoblock structure that is machined from one piece of material. This integration eliminates the need for separate components and assembly operations, reducing manufacturing complexity and cost while maintaining the broadband performance required for high-frequency applications. The single-piece construction also eliminates potential alignment issues between multiple parts.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

While the overall structure is a single piece, the patent incorporates internal segmentation through the ridge structure that divides the rotator portion into distinct functional zones. This internal segmentation allows different regions of the monoblock to perform specific functions (polarization rotation, mode control) without requiring separate physical components, thus maintaining simplicity while achieving complex electromagnetic performance.

Inventive Principle:
Principle #1Segmentation

3Reliability

If waveguide dimensions are increased to accommodate multiple steps, then polarization rotation performance is improved, but machining precision requirements exceed permitted tolerances

Engineering Contradiction:
Improvepolarization rotation accuracyVSAvoidmachining tolerance
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The overlapping nested configuration allows the waveguide sections to share common machining references and datum surfaces. By nesting one section within the spatial envelope of another, the design reduces the overall dimensional chain that would otherwise require cumulative precision, thereby keeping machining tolerances within permissible limits while maintaining rotation accuracy.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 more compact, cost-effective rotator device with improved radioelectric performance, capable of achieving -40dB return loss over a 25% frequency band for a 45° rotation, while simplifying the machining process and reducing the overall size by 28% compared to traditional designs.

Implementation Method 1

The ridge improves the performance of the rotator device by lowering the cut-off frequency of the dominant mode and raising the cut-off frequency of the next higher order mode

Methodology Applied
Scientific EffectWaveguide mode cut-off frequency: Waveguide

Data Source

PatentEP3499636B1A rotator device for connecting non-aligned waveguides and a method of manufacture thereof
Publication Date: 2021.09.08 ALCATEL LUCENT SHANGHAI BELL CO LTD
  • EP3499636B1 patent drawingFigure 1~2
  • EP3499636B1 patent drawingFigure 3~4
  • EP3499636B1 patent drawingFigure 5

AI summary

A rectangular waveguide rotator device for connecting first and second waveguides, the first and second waveguides being arranged at an angle to each other is disclosed. The rotator device comprises: at least one rotator portion, the at least one rotator portion comprising a passage formed by outer walls comprising two longer walls connected by two shorter end walls; the at least one rotator portion comprising a ridge protruding from each of the longer side walls across a width of the longer side walls, the ridge lying between a first and a further section of the rotator portion; the first and further sections of the rotator portion being configured such that they are at an angle with respect to each other, one section being rotated through an angle with respect to the other.