Dielectric Antenna Stepped Impedance Converter for Compact Level Measurement

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Solution Overview

Problem

Dielectric antennas face a trade-off between achieving a narrow main radiation direction and a compact design, as a narrow directional characteristic requires a large aperture, which contradicts the need for a compact form factor, especially in level measurement technology where installation constraints limit the antenna's size and lead to parasitic reflections.

Innovation Solution

The dielectric antenna incorporates a stepped impedance converter principle in its radiation section, allowing for mode-pure excitation and variability in length, with a non-linear inner contour in the second transition section and a metallic horn attachment to enhance directivity and reduce reflections, while maintaining a compact design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the aperture of the radiation section is increased to achieve a narrow main radiation direction, then the directivity is improved, but the antenna extension perpendicular to the main radiation direction increases, contradicting the compact design requirement

Engineering Contradiction:
Improvemain radiation direction narrownessVSAvoidaperture area
Core Design Contradiction:
Length of moving objectVSArea of moving object

Solution Approach 1:

The antenna is divided into multiple sections with different functions: a feed section, a first transition section with a dielectric rod, a second transition section forming a dielectric horn, and a radiation section. This segmentation allows each section to be optimized independently, enabling compact overall design while achieving narrow beamwidth through the horn section's geometry

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from a simple rod geometry to a horn geometry in the second transition section, adding dimensional complexity to the radiation structure. This dimensional change allows the aperture to be effectively increased in the radiation direction without proportionally increasing the overall antenna footprint, thereby achieving narrow beamwidth in a compact form

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

2Length of moving object

If the antenna length is increased to achieve a flat phase front for narrow directional characteristic, then the directivity is improved, but the compact design requirement is contradicted

Engineering Contradiction:
Improveantenna lengthVSAvoidantenna volume
Core Design Contradiction:
Length of moving objectVSVolume of moving object

Solution Approach 1:

The patent employs parameter changes in the horn section geometry, specifically using a non-linear inner contour that opens increasingly in the radiation direction. This parameter optimization allows the phase front to be flattened with a shorter antenna length compared to linear horn designs, achieving narrow beamwidth while maintaining compact volume

Inventive Principle:
Principle #35Parameter changes

3Length of moving object

If the geometric aperture is increased to achieve narrow main radiation direction, then the directivity is improved, but the antenna can no longer penetrate into the volume to be monitored through existing tank openings and nozzles

Engineering Contradiction:
Improvemain radiation direction narrownessVSAvoidinstallation adaptability
Core Design Contradiction:
Length of moving objectVSAdaptability or versatility

Solution Approach 1:

The patent applies local quality optimization by concentrating the aperture function specifically in the horn section rather than uniformly across the entire antenna. This allows the critical aperture area to be optimized for narrow beamwidth while the overall antenna diameter remains small enough to fit through standard tank openings and nozzles, maintaining installation adaptability

Inventive Principle:
Principle #3Local quality

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 achieves high directivity and reduced reflections, enabling efficient level measurement with improved bundling properties and minimal interference, allowing the antenna to be adapted to various installation situations with minimal loss and low reflection.

Implementation Method 1

The electromagnetic wave guided by the waveguide propagates via the dielectric feed section into the first transition section comprising the dielectric rod

Methodology Applied
Scientific EffectElectromagnetic wave propagation: Electromagnetic Induction

Implementation Method 2

the radiation section designed as a dielectric tube towards the free space is designed as a stepped impedance converter according to the principle of a quarter-wave transformer

Methodology Applied
Scientific EffectImpedance transformation: Electromagnetic Induction

Implementation Method 3

the first transition section and the second transition section receiving electromagnetic radiation can be guided

Methodology Applied
Scientific EffectElectromagnetic wave guidance: Waveguide

Data Source

PatentEP2840653B1Dielectric antenna
Publication Date: 2015.10.21 KROHNE MESSTECHNICK GMBH & CO KG
  • EP2840653B1 patent drawingFigure 1
  • EP2840653B1 patent drawingFigure 2
  • EP2840653B1 patent drawingFigure 3

AI summary

A dielectric antenna (1) is described and illustrated, comprising a dielectric feed section (2), a first transition section (3) including a dielectric rod, a second transition section (4) forming a dielectric horn, and a dielectric radiating section (5). The feed section (2) can be supplied with electromagnetic radiation (6), the first transition section (3) and the second transition section (4) can guide electromagnetic radiation (6), and the electromagnetic radiation (6) can be radiated from the radiating section (5) as a free-space wave. The radiating section (5) is designed as a dielectric tube with an outer diameter adjoining the second transition section (4).The object of the present invention is to provide a dielectric antenna that can be adapted to various installation situations with minimal loss, and which is also highly directional and exhibits minimal reflection. This object is achieved in the aforementioned dielectric antenna by designing the radiating section (5), which is configured as a dielectric tube, as a stepped impedance converter (19) based on the principle of a quarter-wave transformer.