Split Dielectric Rotary Joint for High-Bandwidth mm-Wave Data

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Solution Overview

Problem

Current contactless rotating couplers for high-speed data transmission in the mm-wave range are complex, costly, and difficult to maintain, with limited bandwidth and data rate, particularly in applications like CT scanners.

Innovation Solution

A contactless datalink using a ring-shaped dielectric waveguide split into two components with a gap, allowing for simple installation and maintenance, featuring a low dielectric constant material like PTFE, and employing 3dB couplers for bidirectional signal transmission without phase change, optimized for the EHF frequency range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a traditional capacitive rotary joint with strip line is used, then the structure is simple, but the bandwidth is limited to a few GHz and data rate is limited to a few Gbit/s

Engineering Contradiction:
Improvestructure simplicityVSAvoidbandwidth capability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent changes the fundamental operating parameters by transitioning from capacitive coupling at a few GHz to dielectric waveguide-based electromagnetic coupling in the EHF range (60 GHz and above). This parameter change enables significantly higher bandwidth and data rates while maintaining structural simplicity through the use of a split ring dielectric waveguide configuration.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If complex couplers are used to couple signals into and out of the dielectric waveguide, then signal coupling efficiency improves, but the device complexity increases and cost increases

Engineering Contradiction:
Improvesignal coupling efficiencyVSAvoidcoupler complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the dielectric waveguide into two separate components: a stationary part and a rotating part. This segmentation allows for simple mechanical coupling through a gap without requiring complex coupler structures. The electromagnetic field couples signals between the two segments across the gap, achieving efficient signal transmission while maintaining structural simplicity and reducing cost.

Inventive Principle:
Principle #1Segmentation

3Reliability

If a closed ring dielectric waveguide is used, then signal transmission is continuous, but installation and maintenance become difficult

Engineering Contradiction:
Improvesignal transmission continuityVSAvoidmaintenance accessibility
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

By dividing the closed ring dielectric waveguide into two separable components (stationary and rotating parts), the patent enables easy installation and maintenance. The components can be independently accessed, removed, and replaced without disassembling the entire structure, while still maintaining continuous signal transmission through electromagnetic coupling across the gap.

Inventive Principle:
Principle #1Segmentation

4Reliability

If a dielectric waveguide with high dielectric constant is used, then signal guidance is improved, but signal losses increase in the EHF frequency range

Engineering Contradiction:
Improvesignal guidance capabilityVSAvoidsignal attenuation
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent optimizes the dielectric constant parameter to be low (between 1.5 and 3.5) specifically for EHF frequency range operation. This parameter optimization reduces signal losses and attenuation at these frequencies while maintaining adequate signal guidance capability through the dielectric waveguide structure.

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 provides a cost-effective, easy-to-maintain, high-bandwidth data transmission system with increased data rate capabilities, suitable for applications like CT scanners, by utilizing a split dielectric waveguide with low-loss materials and 3dB couplers, ensuring efficient signal coupling and low attenuation.

Implementation Method 1

The rotating and stationary parts are rotatable around said axis of rotation... Any configuration allows coupling of signals from either side to the other side

Methodology Applied
Scientific EffectElectromagnetic coupling: Electromagnetic Induction

Implementation Method 2

The waveguide preferably has a low dielectric constant and low losses in the frequency range of and above 60GHz... Preferred materials are plastics with a low relative dielectric constant (1.5 to 3.5) and low losses

Methodology Applied
Scientific EffectDielectric property: Dielectric

Data Source

PatentEP3886329B1Rotary joint with dielectric waveguide
Publication Date: 2024.03.06 SCHLEIFRING GMBH
  • EP3886329B1 patent drawingFigure 1a~1c
  • EP3886329B1 patent drawingFigure 2
  • EP3886329B1 patent drawingFigure 3~4

AI summary

A contactless datalink for transmission of data between a rotating part and a stationary part, the datalink comprises a dielectric waveguide which is split into two sections, wherein a first dielectric waveguide section is at the rotating part and a second dielectric waveguide section is at the stationary part. The first dielectric waveguide section is coupled to a transmitter and the second dielectric waveguide section is coupled to a receiver.