Helix Conductor Sensor Stray Field Reduction

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Solution Overview

Problem

Helix resonators in measuring devices suffer from strong stray fields, which degrade the quality of the measuring field and reduce the accuracy of resonance measurements, necessitating an improvement in the design to enhance signal penetration and measurement precision.

Innovation Solution

The solution involves a sensor design where the helix conductor is galvanically coupled at both ends to the electrically conductive shell structure, eliminating stray fields and allowing for effective penetration of the electric field into the sample, while using a low measuring frequency to improve measurement accuracy and reduce interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the helix conductor is used in a measuring device, then resonance measurement can be performed, but strong stray fields are generated that degrade measurement quality

Engineering Contradiction:
Improvemeasurement qualityVSAvoidstray fields
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent extracts and eliminates the harmful stray fields generated by the helix conductor ends through galvanic coupling to the conductive shell. By connecting both ends of the helix conductor to the electrically conductive shell structure, the stray fields are suppressed and removed from the measuring chamber, thereby improving measurement quality without sacrificing the resonance measurement capability.

Inventive Principle:
Principle #2Taking out (Extraction)

2Device complexity

If the helix conductor ends are left open, then the structure is simple, but stray fields are generated that reduce measurement accuracy

Engineering Contradiction:
Improvestructure simplicityVSAvoidmeasurement accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent merges the helix conductor ends with the electrically conductive shell structure through galvanic coupling. Both ends of the helix conductor are connected to the shell, creating a unified electrical structure that suppresses stray fields while maintaining structural simplicity. This merging eliminates the need for additional complex termination structures.

Inventive Principle:
Principle #5Merging (Combining)

3Productivity

If high measuring frequency is used, then measurement speed is improved, but interference and measurement accuracy are reduced

Engineering Contradiction:
Improvemeasurement speedVSAvoidmeasurement accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent changes the operating parameter by using low measuring frequency instead of high frequency. This parameter change reduces interference and improves measurement accuracy while the galvanic coupling structure ensures that measurement speed remains adequate by suppressing stray fields that would otherwise cause interference at any frequency.

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 effectively reduces stray fields, enhances measurement accuracy, and allows for precise determination of properties like water content and dry content in samples, improving the overall quality of resonance measurements.

Implementation Method 1

The radio-frequency resonance of the helix resonator depends, among other things, on the permittivity of the material inside the helical conductor

Methodology Applied
Scientific EffectRadio-frequency resonance: Resonance

Implementation Method 2

both ends of the helix conductor (110) having the same coupling to the shell structure (106) of the chamber, wherein the shell structure (106) is made of an electrically conductive material

Methodology Applied
Scientific EffectStray field reduction through galvanic coupling: Conduction (electrical)

Data Source

PatentEP2952887B1Sensor, measuring device, and measuring method for measuring the permittivity of a sample using a helix conductor
Publication Date: 2019.01.30 SENFIT OY
  • EP2952887B1 patent drawingFigure 1~2
  • EP2952887B1 patent drawingFigure 3~4
  • EP2952887B1 patent drawingFigure 5~7

AI summary

A sensor for measuring a sample in a measuring cell comprising a helix conductor (110) located at the measuring cell (108) elsewhere than in the space enclosed by the measuring cell (108), the shell structure (112) of the measuring cell (108) being made of an electrically non-conductive material. The measuring cell (108) and at least part of the helix conductor (110) are placeable inside a chamber (104). The chamber (104) comprises a shell structure (106) made of an electrically conductive material. The coupling of both ends (114, 116) of the helix conductor (110) to the shell structure (106) of the chamber (104) is the same. A radio-frequency signal input element (102) couples a radio-frequency signal to the chamber (104) for the purpose of forming at least one helix resonance to the helix conductor (110). A radio-frequency signal output element (124) is responsive to at least one helix resonance of the helix conductor (110) and transmits a radio-frequency signal for measurement. A device for measuring a sample in a measuring cell comprises said sensor, a radio-frequency signal source (100), and a measuring and control part (122). The radio-frequency signal source (100) produces a radio-frequency signal to the input element (102). The measuring and control part (122) measures at least one property of a sample (130) on the basis of at least one resonance frequency.