EP1352233A2 - Detecteur micro-ondes a resonance - Google Patents

Detecteur micro-ondes a resonance

Info

Publication number
EP1352233A2
EP1352233A2 EP02700148A EP02700148A EP1352233A2 EP 1352233 A2 EP1352233 A2 EP 1352233A2 EP 02700148 A EP02700148 A EP 02700148A EP 02700148 A EP02700148 A EP 02700148A EP 1352233 A2 EP1352233 A2 EP 1352233A2
Authority
EP
European Patent Office
Prior art keywords
sensor
microwave
waveguide
spiral conductor
microwave sensor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP02700148A
Other languages
German (de)
English (en)
Inventor
Bert Dipl.-Ing. JANNSEN
Arne Prof.Dr.-Ing. Jacob
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Technische Universitaet Bergakademie Freiberg
TECHNISCHE UNIVERSITAT
Original Assignee
Technische Universitaet Bergakademie Freiberg
TECHNISCHE UNIVERSITAT
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Technische Universitaet Bergakademie Freiberg, TECHNISCHE UNIVERSITAT filed Critical Technische Universitaet Bergakademie Freiberg
Publication of EP1352233A2 publication Critical patent/EP1352233A2/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N22/00—Investigating or analysing materials by the use of microwaves or radio waves, i.e. electromagnetic waves with a wavelength of one millimetre or more

Definitions

  • the invention relates to a resonant microwave sensor for determining properties of a material to be examined by means of the high-frequency measurement of a reflection factor
  • a microwave feeder for supplying the high-frequency signal
  • the measurement of material properties with microwave sensors by evaluating resonance frequencies and the quality of a resonance curve, which is recorded by applying a wobbled high-frequency signal to the microwave sensor, is well known.
  • the signal with variable frequency is coupled into the microwave sensor and the resonance frequency and, if necessary, the quality is determined.
  • German utility model 297 16 639 U1 a microwave stray field sensor for moisture and / or density measurement is described, in which a moist dielectric material is introduced into the resonator and the density and moisture of the material is determined by shifting the resonance frequency.
  • the wavelength at the location of the generation of the resonance signal is significantly less than in the free space of the resonator.
  • the resonator is designed as a wire loop, which is surrounded by a thin dielectric.
  • the resonator is formed from a circular dielectric ceramic body, the microwaves being coupled into the resonator via coaxial lines and capacitive coupling pins.
  • US Pat. No. 3,946,308 describes a microwave sensor for moisture measurement which consists of a dielectric resonator with a metallic conductor made of a solid dielectric material, and an inlet and an outlet antenna.
  • DE-OS 24 54 788 A1 discloses a method and a device for determining the moisture of a gaseous medium.
  • This document describes the basic procedure for measuring the moisture of a medium using the circular quality of a resonance curve.
  • a microwave oscillation of variable frequency that is to say a wobbled signal, is coupled into the resonator and is coupled out again separately therefrom.
  • the amplitudes of the coupled vibrations are measured and recorded as a function of the frequency with constant amplitudes of the coupled vibrations.
  • the problem with the known resonant microwave sensors which are based on the reflection method, consists in scattering losses, broadband and the size.
  • the known microwave sensors can also not be optimally integrated into structures for in-situ measurement of the characteristic material properties.
  • the object of the invention was therefore to create an improved generic resonant microwave sensor.
  • the task is solved by a spiral conductor which is arranged within the sensor waveguide.
  • spiral conductor as a resonant metallic helix allows the construction of a compact sensor waveguide as a resonator.
  • the resonance frequency of the microwave sensor can also be set using the spiral conductor.
  • the sensor waveguide as a resonator is preferably a cylindrical tube, the microwave feeder being arranged, for example, as a coaxial waveguide on a first end face of the sensor waveguide.
  • the second end face of the sensor waveguide is open so that the material to be examined can penetrate the resonator.
  • the properties of the material to be examined such as the relative air humidity, can be determined in a known manner.
  • the resonance frequency and quality of the sensor waveguide are calculated from the reflection factor R.
  • the spiral conductor preferably extends in the longitudinal direction of the sensor waveguide.
  • the spiral conductor is preferably held by a carrier and centered in the sensor waveguide.
  • an intermediate layer is advantageously provided between the first end face of the sensor waveguide and the spiral conductor.
  • the thickness of the intermediate layer determines the coupling factor.
  • the quality of the sensor can be adjusted with the intermediate layer.
  • the thickness of the intermediate layer should be chosen so that the greatest possible coupling is achieved.
  • the resonance frequency of the microwave sensor is largely determined by the dimension of the spiral conductor.
  • an additional coupling layer is provided between the spiral conductor and the substance to be examined or a sensitive layer in the region of the second end face of the sensor waveguide.
  • the thickness of the coupling layer determines the coupling of the spiral conductor to the material to be examined and thus the measurement sensitivity.
  • the frequency of the wobbled signal for exciting the microwave sensor should be less than the cutoff frequency of the microwave sensor.
  • the length of the sensor waveguide should be sufficiently large to avoid radiation to the outside and thus scattering losses.
  • the carrier and the intermediate layer are preferably made in one piece.
  • the intermediate layer and / or the carrier consists of Teflon.
  • FIG. 1 Schematic representation of the microwave sensor according to the invention
  • FIG. 2 - schematic representation of the microwave sensor according to the invention with intermediate layer and coupling layer;
  • FIG. 4 diagram of the amount of reflection factor for various measured relative air humidities
  • Figure 5 Diagram of the resonance shift depending on the relative humidity as a calibration curve for the microwave sensor.
  • FIG. 1 shows a resonant microwave sensor 1 according to the invention, which is installed with a sensor waveguide 2 as a resonator in the material 3 to be examined.
  • the microwave sensor 1 essentially consists of a microwave feeder 4 in the form of a coaxial waveguide and the sensor waveguide 2 as a resonator.
  • a helical conductor 5 is arranged in the sensor waveguide 2 and extends in the longitudinal direction of the sensor waveguide 2.
  • the spiral conductor 5 is a resonant conductive helix.
  • the sensor waveguide 2 is filled with a material 6, which is sensitive to the substance or property of the material 3 to be examined.
  • a material 6 which is sensitive to the substance or property of the material 3 to be examined.
  • the wobbled high-frequency signal is applied to the microwave sensor 1 in a frequency range adapted to the material 3 to be examined and the microwave sensor 1, and the reflection factor r is measured in a known manner.
  • the sensor waveguide 2 is coupled to the microwave feeder 4 on a first end face 7 and is open on the second end face 8.
  • the substances to be detected can penetrate into the sensor waveguide 2 through the open second end face 8, for example by diffusion or through the gas phase.
  • the dielectric properties of the sensitive filling of the sensor waveguide 2 are changed and the characteristic sizes of the resonator, that is called the resonance frequency and quality, detuned.
  • the dimensions of the sensor waveguide 2 as a resonator are in conventional round waveguide resonators essentially by the cut-off frequencies f Q
  • Natural waves of the circular waveguide (E or H waves) and the dielectric constant and permeability of the filling of the sensor waveguide 2.
  • the length of the sensor waveguide 2 can be variable.
  • the radius of the sensor waveguide 2 is determined approximately according to the equation E waves.
  • the radius of the sensor waveguide 2 is determined approximately according to the equation H waves
  • the sensor waveguide 2 can be made much more compact by attaching the helix 5 in the sensor waveguide 2.
  • the re- The resonance frequency of the resonator is essentially determined by the dimensions, that is to say by the wire length, the radius and the pitch of the helical conductor 5.
  • FIG. 2 shows a further embodiment of the microwave sensor, in which an intermediate layer a, preferably made of Teflon, is arranged between the first end face 7 of the sensor waveguide 2 and the spiral conductor 5.
  • This intermediate layer a is used to adjust the distance and thus the coupling between the microwave feeder 4 and the helical conductor 5.
  • the quality of the microwave sensor 1 can essentially be adjusted with the intermediate layer a.
  • the thickness of the intermediate layer should be chosen so that the greatest possible coupling is achieved. This allows the measurement dynamics to be increased.
  • the spiral conductor 5 can be held on the intermediate layer a with a carrier centrally in the sensor waveguide 2.
  • the carrier can be formed integrally with the intermediate layer a.
  • the second layer b is essentially determined by the height of the spiral conductor 5 and essentially determines the resonance frequency.
  • a coupling layer c is provided above the spiral conductor 5, which determines the coupling of the spiral conductor 5 to the sensitive material 9 for the detection of the substance to be measured and thus the sensitivity of the measurement.
  • the thickness c of the coupling layer and the thickness d of the sensitive material 9 must be selected to be sufficiently large in order to emit, i.e. Avoid scatter from the sensor waveguide 2.
  • the structure of the microwave sensor 1 is shown again in cross section in FIG. 3. It can be seen here that the microwave feeder 4 is screwed into the sensor waveguide 2, which is provided with a microwave plug, in the form of a flexible coaxial waveguide. It is still the one Intermediate layer a with the integrally connected support for the spiral conductor 5 and the spiral conductor 5 can be seen.
  • the microwave sensor 1 is preferably used in a frequency range from 1 to 6 GHz.
  • the wire diameter of the spiral conductor 5 is preferably approximately 0.2 mm and the ratio of the diameter to the pitch of the spiral conductor 5 is in the range of approximately 75.
  • FIG. 4 shows a diagram of the amount of reflection factor for different relative air humidities depending on the frequency. It becomes clear that the resonance frequencies shift depending on the relative air humidity, with an increase in the relative air humidity resulting in a reduction in the resonance frequency. It can also be seen that the quality of the resonator decreases with increasing relative humidity.
  • a calibration curve for the microwave sensor can be determined from the measured reflection factors, which is plotted in FIG. 5 as a resonance shift as a function of the relative atmospheric humidity. Using the calibration curve, it is possible to infer the relative air humidity directly from the resonance frequency in subsequent measurements.
  • the use of the microwave sensor 1 is not limited to the use as a moisture sensor. It can also be used to measure material properties that lead to a change in the dielectric properties of the sensitive material in the sensor waveguide 2.

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Measurement Of Resistance Or Impedance (AREA)
  • Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)

Abstract

L'invention concerne un détecteur micro-ondes à résonance (19 utilisé pour déterminer les propriétés d'un matériau (3) à examiner, par mesure haute fréquence d'un facteur de réflexion (r) d'un signal de résonance haute fréquence comme grandeur mesurée pour déterminer des propriétés d'une substance à examiner. Ledit détecteur micro-ondes comprend un conducteur d'amenée de micro-ondes (4) pour acheminer le signal haute fréquence, un détecteur-guide d'ondes (2) couplé au conducteur d'amenée de micro-ondes (4) et comporte un conducteur spiralé (5), monté dans le détecteur-guide d'ondes (2).
EP02700148A 2001-01-20 2002-01-10 Detecteur micro-ondes a resonance Withdrawn EP1352233A2 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE10102578 2001-01-20
DE10102578A DE10102578C2 (de) 2001-01-20 2001-01-20 Resonanter Mikrowellensensor
PCT/DE2002/000054 WO2002057762A2 (fr) 2001-01-20 2002-01-10 Detecteur micro-ondes a resonance

Publications (1)

Publication Number Publication Date
EP1352233A2 true EP1352233A2 (fr) 2003-10-15

Family

ID=7671242

Family Applications (1)

Application Number Title Priority Date Filing Date
EP02700148A Withdrawn EP1352233A2 (fr) 2001-01-20 2002-01-10 Detecteur micro-ondes a resonance

Country Status (5)

Country Link
US (1) US6798216B2 (fr)
EP (1) EP1352233A2 (fr)
AU (1) AU2002233155A1 (fr)
DE (1) DE10102578C2 (fr)
WO (1) WO2002057762A2 (fr)

Families Citing this family (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6917726B2 (en) * 2001-09-27 2005-07-12 Cornell Research Foundation, Inc. Zero-mode clad waveguides for performing spectroscopy with confined effective observation volumes
EP1790202A4 (fr) * 2004-09-17 2013-02-20 Pacific Biosciences California Appareil et procede d'analyse de molecules
US7170050B2 (en) 2004-09-17 2007-01-30 Pacific Biosciences Of California, Inc. Apparatus and methods for optical analysis of molecules
US7836910B2 (en) 2004-12-29 2010-11-23 Rain Bird Corporation Soil moisture sensor and controller
DE102006036188B4 (de) * 2006-08-01 2011-06-16 Franz Ludwig Gesellschaft für Mess- und Regeltechnik mbH Resonanter Mikrowellensensor
DE102006036190A1 (de) * 2006-08-01 2008-02-14 Technische Universität Braunschweig Carolo-Wilhelmina Schaltungsanordenung zur Erzeugung eines mit einer Oszillationsfrequenz oszillierenden elektromagnetischen Signals
RU2331894C1 (ru) * 2007-02-14 2008-08-20 Открытое акционерное общество Научно-производственная Компания "Высокие Технологии" Способ измерения диэлектрических характеристик материальных тел и устройство для его реализации
AU2009229157B2 (en) 2008-03-28 2015-01-29 Pacific Biosciences Of California, Inc. Compositions and methods for nucleic acid sequencing
IT1391515B1 (it) * 2008-09-26 2011-12-30 Giuseppe Cristini S P A Sa Dispositivo e metodo per la misura della permeabilita' all'acqua di un materiale
US8829924B2 (en) * 2012-08-20 2014-09-09 Smart Autonomous Solutions, Inc. Method and apparatus for monitoring physical properties
NL1041088B1 (en) * 2013-12-16 2016-05-19 Stichting Wetsus Centre Of Excellence For Sustainable Water Tech Method and device for measuring dielectric properties of a fluidum in a modified coaxial stub resonator.
RU2559840C1 (ru) * 2014-04-29 2015-08-10 Федеральное государственное казенное военное образовательное учреждение высшего профессионального образования "Военный учебно-научный центр Военно-воздушных сил "Военно-воздушная академия имени профессора Н.Е. Жуковского и Ю.А. Гагарина" (г. Воронеж) Министерства обороны Российской Федерации Свч-способ определения осажденной влаги в жидких углеводородах
FI127021B (fi) 2014-06-02 2017-09-29 Senfit Oy Anturi, mittalaite ja mittausmenetelmä
NO20140689A1 (no) * 2014-06-03 2015-12-04 Roxar Flow Measurement As Cutoff regulator
CN113740353B (zh) * 2021-07-31 2022-10-14 西南大学 一种基于衬底集成波导双重入式谐振腔的差分湿度传感器

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DE4432687A1 (de) * 1994-09-14 1996-03-21 Karlsruhe Forschzent Feuchtesensor und dessen Verwendung
EP0948078A2 (fr) * 1998-04-02 1999-10-06 Space Systems / Loral, Inc. Filtres à cavité monomode et bimode chargé par hélice

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FI844061L (fi) * 1984-10-16 1986-04-17 Kemira Oy Foerfarande och anordning foer maetning av fukthalten eller torrsubstanshalten av aemnen.
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DE4432687A1 (de) * 1994-09-14 1996-03-21 Karlsruhe Forschzent Feuchtesensor und dessen Verwendung
EP0948078A2 (fr) * 1998-04-02 1999-10-06 Space Systems / Loral, Inc. Filtres à cavité monomode et bimode chargé par hélice

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See also references of WO02057762A3 *

Also Published As

Publication number Publication date
US6798216B2 (en) 2004-09-28
DE10102578A1 (de) 2002-08-01
US20030137313A1 (en) 2003-07-24
AU2002233155A1 (en) 2002-07-30
DE10102578C2 (de) 2003-01-09
WO2002057762A3 (fr) 2002-12-05
WO2002057762A2 (fr) 2002-07-25

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