Dielectric Waveguide Transition for Low-Loss Radar Antennas

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Solution Overview

Problem

The transition from a rectangular waveguide to a circular waveguide introduces significant insertion and attenuation losses, leading to pseudo-echoes in radar signals and requiring a space-consuming arrangement.

Innovation Solution

A waveguide arrangement with a dielectric-filled circular waveguide projecting into a rectangular waveguide at a defined angle, featuring a beveled transition surface to minimize reflections and reduce losses, allowing for compact and efficient signal transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a transition from rectangular waveguide to circular waveguide is implemented, then the antenna can be rotationally symmetrical, but insertion and attenuation losses increase significantly

Engineering Contradiction:
Improveantenna symmetryVSAvoidinsertion and attenuation losses
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

A dielectric material is introduced as an intermediary substance filling the circular waveguide to improve the transition from rectangular to circular waveguide. The dielectric modifies the electromagnetic field distribution and impedance characteristics, enabling better mode matching between the two waveguide types and reducing insertion losses while maintaining rotational symmetry

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies physical parameters of the transition structure including the dielectric constant of the filling material, the dimensions of the circular waveguide, and the geometry of the transition section. By optimizing these parameters, the impedance mismatch between rectangular and circular waveguides is reduced, minimizing reflections and energy losses

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If a transition from rectangular waveguide to circular waveguide is implemented, then the antenna can be rotationally symmetrical, but pseudo-echoes occur in radar signals

Engineering Contradiction:
Improveantenna symmetryVSAvoidpseudo-echoes
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The dielectric material serves as a mediator that smooths the electromagnetic field transition between rectangular and circular waveguides. By controlling the field distribution and reducing abrupt impedance changes, the dielectric minimizes signal reflections that would otherwise create pseudo-echoes in radar measurements

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

Optimization of the dielectric constant and transition section geometry modifies the electromagnetic parameters to reduce standing waves and signal reflections. The optimized parameters ensure smooth field transformation, eliminating the conditions that generate harmful pseudo-echoes

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If a transition from rectangular waveguide to circular waveguide is implemented, then the antenna can be rotationally symmetrical, but the arrangement becomes space-consuming

Engineering Contradiction:
Improveantenna symmetryVSAvoidarrangement volume
Core Design Contradiction:
Adaptability or versatilityVSVolume of stationary object

Solution Approach 1:

The circular waveguide with dielectric filling is nested into the rectangular waveguide structure in a compact transition arrangement. The dielectric-filled circular waveguide is positioned within the bounds of the rectangular waveguide, creating a space-efficient transition that maintains rotational symmetry without requiring additional space

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 beveled dielectric transition reduces reflections and attenuation, enabling low-loss signal transmission and compact antenna arrays for 3D radar systems.

Implementation Method 1

This bevel reduces reflections, resulting in a low-loss transition with low reflection and attenuation

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

The electromagnetic, high-frequency wave is thus guided from the injection point through the rectangular waveguide to the circular waveguide

Methodology Applied
Scientific EffectElectromagnetic wave propagation: Waveguide

Data Source

PatentEP3813188B1Waveguide arrangement and antenna
Publication Date: 2026.01.14 VEGA GRIESHABER GMBH & CO
  • EP3813188B1 patent drawingFigure 1
  • EP3813188B1 patent drawingFigure 2~3
  • EP3813188B1 patent drawingFigure 4

AI summary

The invention relates to a waveguide arrangement (100, 600) for guiding electromagnetic waves, comprising a rectangular waveguide (102) and a circular waveguide (104). The rectangular waveguide (102) transitions into the circular waveguide (104) at an angle. The circular waveguide (104) is filled with a dielectric (116) that projects into the rectangular waveguide (102) at a transition section. The dielectric filling (116) is chamfered at a defined angle in the transition section, so that a transition surface (126) is formed by the inner edge (110) at the transition of the waveguide arrangement (100) and the end face (124) of the rectangular waveguide (102) at the transition. The dielectric filling (116) is preferably flush with the end wall of the rectangular waveguide (102).