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Chipless Wireless High-Temperature Sensing in Time-Variant Environments

Kubina, Bernd (2017):
Chipless Wireless High-Temperature Sensing in Time-Variant Environments.
Darmstadt, Technische Universität, [Online-Edition: http://tuprints.ulb.tu-darmstadt.de/6785],
[Ph.D. Thesis]

Abstract

The wireless sensing of various physical quantities is demanded in numerous applications. A usual wireless sensor is based on the functionality of semiconductor Integrated Circuits (ICs), which enable the radio communication. These ICs may limit the application potential of the sensor in certain specific applications. One of these applications stands in the focus of this thesis: the operation in harsh environments, e.g., at high temperatures above 175°C, where most available sensors fail. Chipless wireless sensors are researched to exceed such chip-based limitations. A chipless sensor is setup as an entirely electro-magnetic circuit, and uses passive Radio Frequency (RF) backscatter principles to encode and transmit the measured value. Chipless sensors that target harsh environment operation are facing two important challenges: First, the disturbance by clutter, caused by time-variant reflections of the interrogation signal in the sensor environment and second, the design of suitable measurand transducers. These challenges are addressed in the thesis. To overcome the first challenge, three basic chipless sensor concepts feasible for operation in clutter environments are introduced. The concepts are realized by demonstrator designs of three temperature sensors and are proofed by wireless indoor measurements. A channel estimation method is presented that dynamically estimates and suppresses clutter signals to reduce measurement errors. To overcome the second challenge, measurand-sensitive dielectric materials are used as measurement transducers, and are being characterized by a novel high-temperature microwave dielectric characterization method. Complex permittivity characterization results in temperatures up to 900°C are presented. Finally, in-depth description and discussion of the three chipless concepts is given as well as a performance comparison in wireless indoor measurement scenarios. The first concept is based on polarization separation between the wanted sensor backscatter signal and unwanted clutter. The second concept separates tag and clutter signals in the frequency domain by using harmonic radar. The third concept exploits the slow decay of high-Q resonances in order to achieve the desired separation in time domain. This concept’s realization is based on dielectric resonators and has demon- strated the capability of wirelessly measuring temperatures up to 800°C without requiring an optical line-of-sight. This performance significantly exceeds temperature- and detection-limitations of commercially available sensors at the current state-of-the-art.

Item Type: Ph.D. Thesis
Erschienen: 2017
Creators: Kubina, Bernd
Title: Chipless Wireless High-Temperature Sensing in Time-Variant Environments
Language: English
Abstract:

The wireless sensing of various physical quantities is demanded in numerous applications. A usual wireless sensor is based on the functionality of semiconductor Integrated Circuits (ICs), which enable the radio communication. These ICs may limit the application potential of the sensor in certain specific applications. One of these applications stands in the focus of this thesis: the operation in harsh environments, e.g., at high temperatures above 175°C, where most available sensors fail. Chipless wireless sensors are researched to exceed such chip-based limitations. A chipless sensor is setup as an entirely electro-magnetic circuit, and uses passive Radio Frequency (RF) backscatter principles to encode and transmit the measured value. Chipless sensors that target harsh environment operation are facing two important challenges: First, the disturbance by clutter, caused by time-variant reflections of the interrogation signal in the sensor environment and second, the design of suitable measurand transducers. These challenges are addressed in the thesis. To overcome the first challenge, three basic chipless sensor concepts feasible for operation in clutter environments are introduced. The concepts are realized by demonstrator designs of three temperature sensors and are proofed by wireless indoor measurements. A channel estimation method is presented that dynamically estimates and suppresses clutter signals to reduce measurement errors. To overcome the second challenge, measurand-sensitive dielectric materials are used as measurement transducers, and are being characterized by a novel high-temperature microwave dielectric characterization method. Complex permittivity characterization results in temperatures up to 900°C are presented. Finally, in-depth description and discussion of the three chipless concepts is given as well as a performance comparison in wireless indoor measurement scenarios. The first concept is based on polarization separation between the wanted sensor backscatter signal and unwanted clutter. The second concept separates tag and clutter signals in the frequency domain by using harmonic radar. The third concept exploits the slow decay of high-Q resonances in order to achieve the desired separation in time domain. This concept’s realization is based on dielectric resonators and has demon- strated the capability of wirelessly measuring temperatures up to 800°C without requiring an optical line-of-sight. This performance significantly exceeds temperature- and detection-limitations of commercially available sensors at the current state-of-the-art.

Place of Publication: Darmstadt
Divisions: 18 Department of Electrical Engineering and Information Technology
18 Department of Electrical Engineering and Information Technology > Institute for Microwave Engineering and Photonics > Microwave Engineering
18 Department of Electrical Engineering and Information Technology > Institute for Microwave Engineering and Photonics
Date Deposited: 24 Sep 2017 19:55
Official URL: http://tuprints.ulb.tu-darmstadt.de/6785
URN: urn:nbn:de:tuda-tuprints-67853
Referees: Jakoby, Prof. Dr. Rolf and Vossiek, Prof. Dr. Martin
Refereed / Verteidigung / mdl. Prüfung: 4 November 2016
Alternative Abstract:
Alternative abstract Language
Das drahtlose Messen diverser physikalischer Größen ist in zahlreichen Anwendungen notwendig. Ein klassischer drahtloser Sensor basiert auf der Funktionalität von integrierten Halbleiter-Schaltkreisen (ICs), welche die Funkkommunikation ermöglichen. In spezifischen Anwendungen können diese ICs jedoch das Anwendungspotential des Sensors begrenzen. Eine spezifische Anwendung steht im Fokus dieser Arbeit: der Betrieb in rauhen Umgebungen, z.B. bei hohen Temperaturen oberhalb von 175°C, in denen die meisten verfügbaren Sensoren nicht betriebsfähig sind. Dieser Umstand motiviert die Forschung an chiplosen drahtlosen Sensoren, um die chip-basierten Begrenzungen zu überschreiten. Ein chiploser Sensor ist als vollständig elektromagnetischer Schaltkreis aufgebaut und benutzt passive Rückstreuung von Hochfrequenz-Signalen um den Messwert zu verschlüsseln und zu übertragen. Chiplose Sensoren, welche auf die Anwendung in rauhen Umgebungen abzielen, begegnen zwei wichtigen Herausforderungen: Erstens, der Störung durch Clutter, welcher durch zeitvariante Reflektionen des Abfragesignals in der Umgebung des Sensors hervorgerufen wird und zweitens, dem Entwurf geeigneter Messwertumformer. Diese beiden Herausforderungen werden in der vorliegenden Thesis adressiert. Um die erste Hürde zu überwinden werden drei grundlegende chiplose Sensor-Konzepte eingeführt, welche auf die Realisierbarkeit in rauhen Umgebungen mit Clutter abzielen. Diese drei Konzepte sind als Temperaturmessungs-Demonstratoren realisiert und in drahtlosen Messungen validiert worden. Es wird desweiteren eine Kanalschätzungsmethode für chiplose Systeme präsentiert, welche Clutter-Signale dynamisch schätzt und unterdrückt, um Messfehler zu minimieren. Zur Uberwindung der zweiten Hürde werden Messwert-abhängige Dielektrika als Messwertumsetzer eingesetzt und in einer neuartigen Hochtemperatur-Charakterisierungsmethode im Hochfrequenzbereich analysiert. Ergebnisse der Charakterisierung von komplexen Permittivitäten bei Temperaturen bis 900°C werden präsentiert. Schließlich werden sowohl detaillierte Beschreibungen und Diskussionen der drei chiplosen Konzepte, als auch Leistungsvergleiche in Innenraum Mess-Szenarien vorgestellt. Das erste der drei Konzepte basiert auf der Trennung von Sensor-Nutzsignal und Clutter-Störsignal durch Polarisation. Das zweite Konzept trennt Sensor- und Clutter-Signale im Frequenzbereich durch harmonisches Radar. Das dritte Konzept nutzt das langsame Abklingen hochgütiger Resonanzen um die gewünschte Nutz- und Störsignal-Trennung zu erreichen. Die Realisierung des letzteren basiert auf dielektrischen Resonatoren und demonstriert das drahtlose Messen von Temperaturen bis 800°C ohne die Notwendigkeit einer optischen Sichtverbindung. Diese Leistung erweitert bestehende Detektions- und Temperatur-Begrenzungen kommerzieller Sensoren auf dem aktuellen Stand der Technik signifikant.German
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