Dielectric Waveguide Transition for Lower-Dispersion Multimode Links

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Solution Overview

Problem

Existing waveguide technologies face challenges with mode dispersion and excitation of higher modes during transitions, particularly in dielectric waveguides, which limit data transmission rates and quality.

Innovation Solution

A waveguide arrangement with a dielectric waveguide piece that guides a lower number of modes than the second waveguide, featuring a reduced cross-section and permittivity in the front section and a gradual transition to match the second waveguide, minimizing the excitation of higher modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a dielectric multi-mode waveguide is used to transmit electromagnetic waves, then the waveguide can carry multiple modes simultaneously, but modal dispersion occurs due to different propagation velocities of individual modes, reducing usable power and signal quality

Engineering Contradiction:
Improvedata transmission rateVSAvoidsignal quality
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent changes the geometric parameters of the waveguide transition region, specifically tapering the width from the input waveguide dimensions to the output waveguide dimensions. This gradual geometric transformation modifies the mode propagation characteristics, allowing efficient coupling while suppressing higher-order mode excitation. The taper ratio and length are optimized parameters that control the mode transformation process.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The waveguide transition is designed with a gradual, continuous change in cross-sectional dimensions rather than an abrupt step change. This dynamic geometric transition allows the electromagnetic field to adapt progressively from the input mode configuration to the output multi-mode configuration, minimizing discontinuities that would otherwise excite unwanted higher-order modes.

Inventive Principle:
Principle #15Dynamics

2Productivity

If the cross-sectional area of the dielectric waveguide is increased to support more modes, then higher data rates can be achieved, but waveguide dispersion increases, limiting the maximum achievable data rate

Engineering Contradiction:
Improvedata rateVSAvoidwaveguide dispersion
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The patent optimizes the waveguide dimensional parameters including the core width, cladding thickness, and taper length to achieve the desired mode coupling while controlling dispersion. By carefully selecting these parameters, the waveguide can support multiple modes for high data rates while minimizing the dispersion effects through proper geometric design.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If a transition region is designed to suppress excitation of higher modes, then modal dispersion is reduced, but the transition region length increases, adding to the overall device complexity

Engineering Contradiction:
Improvesignal qualityVSAvoidtransition region length
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent determines the optimal taper length and width ratio by analyzing the electromagnetic field distribution and mode coupling characteristics. This parameter optimization achieves effective higher-mode suppression while keeping the transition region length as short as possible, balancing signal quality with device compactness.

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

This design significantly reduces modal dispersion and allows for high data rates with improved transmission properties, enabling efficient use of multi-mode waveguides without the disadvantages of single-mode systems.

Implementation Method 1

a waveguide transition (4) for transmitting an electromagnetic wave (5) between the first waveguide (2) and the second waveguide (3)

Methodology Applied
Scientific EffectElectromagnetic wave propagation: Electromagnetic Induction

Implementation Method 2

the dielectric waveguide piece (6) is designed to guide a lower number of modes than the second waveguide (3) is capable of guiding, at least in a front section (7) facing the first waveguide (2)

Methodology Applied
Scientific EffectDielectric permittivity: Dielectric Permittivity

Implementation Method 3

Mode dispersion, on the other hand, refers to the different propagation velocities of the individual modes. If higher modes are excited at the transition to the dielectric waveguide or along the guide due to discontinuities, this can lead to a reduction in usable power and signal distortion during data transmission

Methodology Applied
Scientific EffectModal dispersion: Dispersion (of waves)

Data Source

PatentEP3867678B1Waveguide assembly, waveguide passage, and use of a waveguide assembly
Publication Date: 2025.07.09 ROSENBERGER HOCHFREQUENZTECHNIK GMBH & CO KG
  • EP3867678B1 patent drawingFigure 1~4
  • EP3867678B1 patent drawingFigure 5~8

AI summary

The invention relates to a waveguide assembly (1) comprising a first waveguide (2), a second waveguide (3) designed as a dielectric multimode waveguide, and a waveguide transition (4) for transmitting an electromagnetic wave (5) between the first waveguide (2) and the second waveguide (3), having a dielectric waveguide piece (6) which is arranged between the first waveguide (2) and the second waveguide (3). The dielectric waveguide piece (6) is designed so as to be capable of guiding a smaller mode number than the second waveguide (3) at least in a front section (7) facing the first waveguide (2).