Conception et réalisation d'un nouveau capteur de gaz passif communicant à transduction RF

L'objectif de cette étude est de montrer la faisabilité d'un nouveau capteur de gaz a transduction RF, passif et sans fil. Ce nouveau capteur est composé de deux lignes coplanaires sur membrane et d'un résonateur diélectrique (RD). L'association de ces deux éléments permet de réaliser un filtre que nous excitons par une onde électromagnétique hyperfréquence en modes de galerie. Grâce à l'effet de " Relaxation Diélectrique ", nous pouvons détecter une variation de l'ambiance gazeuse par un décalage d'une fréquence de résonance du filtre. Les résultats de simulations électromagnétiques ont montré que la détermination de la fréquence de résonance d'un des modes de galerie permettait de détecter facilement la présence de gaz avec une grande sensibilité. Le développement de ce circuit simulé a été réalisé en deux étapes : la fabrication des lignes coplanaires sur membrane et l'élaboration du résonateur diélectrique à base d'un matériau sensible aux gaz. La réalisation d'un RD en TiO2 a été abordée en collaboration avec le CIRIMAT en utilisant la technique SPS (une voie prometteuse mais non encore maitrisée pour nos structures). Compte tenu des difficultés rencontrées, nous avons validé le concept du capteur en utilisant un résonateur en céramique (BaSmTiOxide) réalisé par Temex-Ceramics. L'assemblage des deux parties du capteur a permis d'obtenir les premiers dispositifs et de les caractériser sous différentes ambiances. Les résultats obtenus coïncident bien avec ceux de simulation ce qui valide le principe et la conception de ce nouveau capteur. Enfin, une dernière partie de l'étude est focalisée sur la communication sans fil de ce capteur passif à l'aide d'un RADAR FMCW.In this work, feasibility of gas sensors based on Titanium Dioxide (TiO2) dielectric resonator, operating with whispering-gallery modes, is presented. The gas or humidity adsorption modifies the TiO2 dielectric permittivity and such modification induces variation in the resonant frequencies of high-Q whispering-gallery modes in the millimeter-wave frequency range. Full-wave electromagnetic simulation demonstrates that the measurement of this variation allows the derivation of few parts-per-million (ppm) fluctuations in gas or humidity concentration. For validation purposes very first prototypes of resonator operating with whispering-gallery modes in the millimeter-wave frequency range are micro-machined. The measured performances confirm that such high-Q resonant modes are very sensitive to small variations in dielectric resonator permittivity. Moreover we validate experimentally that these small variations can be remotely detected from the RADAR interrogation of an antenna loaded by the whispering-gallery modes resonator

Nouveau détecteur de gaz hyperfréquence à modes de galerie

National audienc

Novel millimeter-wave gas sensor using dielectric resonator with sensitive layer on TiO2

International audienceA new generation of gas sensors that operates at millimeter-wave frequency range is presented. The sensor uses a dielectric resonator operating with whispering-gallery modes. Here the dielectric resonator is covered by TiO 2 thin film as sensitive layer. A gas or humidity adsorption makes the TiO 2 dielectric permittivity changing and such changing modifies the resonant frequencies of high-Q whispering-gallery modes within the dielectric resonator. From the measurement of these resonant frequencies the humidity concentration can be derived. Here, the proof of concept is demonstrated through full wave electromagnetic simulations. This humidity (gas) sensor can be remotely interrogated and has great potential for wireless sensing network applications

Trends and Applications of Surface and Bulk Acoustic Wave Devices: A Review

The past few decades have witnessed the ultra-fast development of wireless telecommunication systems, such as mobile communication, global positioning, and data transmission systems. In these applications, radio frequency (RF) acoustic devices, such as bulk acoustic waves (BAW) and surface acoustic waves (SAW) devices, play an important role. As the integration technology of BAW and SAW devices is becoming more mature day by day, their application in the physical and biochemical sensing and actuating fields has also gradually expanded. This has led to a profusion of associated literature, and this article particularly aims to help young professionals and students obtain a comprehensive overview of such acoustic technologies. In this perspective, we report and discuss the key basic principles of SAW and BAW devices and their typical geometries and electrical characterization methodology. Regarding BAW devices, we give particular attention to film bulk acoustic resonators (FBARs), due to their advantages in terms of high frequency operation and integrability. Examples illustrating their application as RF filters, physical sensors and actuators, and biochemical sensors are presented. We then discuss recent promising studies that pave the way for the exploitation of these elastic wave devices for new applications that fit into current challenges, especially in quantum acoustics (single-electron probe/control and coherent coupling between magnons and phonons) or in other fields

New microwave gas detector using dielectric resonator based on a Whispering-Gallery-Mode

International audienceThis work describes a novel concept of gas sensor based on RF-transduction technique. The sensor uses a millimeter-wave planar dielectric resonator operating with Whispering-Gallery-Modes. The dielectric resonator incorporates a sensitive material (TiO2 or SnO2) and two coplanar waveguides coupled to its input and output. In presence of gas, the dielectric permittivity of the resonator is modified and the resonant frequencies of some Whispering-Gallery-Modes are then significantly changed. The proof of concept is demonstrated here, through full wave electromagnetic simulations

Nouveau capteur de gaz hyperfréquence à base d'un résonateur diélectrique en SnO2

Prix du meilleur PosterNational audienc

Conception et réalisation d'un nouveau capteur de gaz passif communicant à transduction RF

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF

Feasibility of passive gas sensor based on Whispering Gallery Modes and its Radar interrogation: theoretical and experimental investigations

International audienceFeasibility of gas sensors based on Titanium Dioxide (TiO2) dielectric resonator operating with whispering-gallery modes is presented. The gas or humidity adsorption modifies the TiO2 dielectric permittivity and such modification induces variation in the resonant frequencies of high-Q whispering-gallery modes in the millimeter-wave frequency range. Full-wave electromagnetic simulation indicates that the measurement of this variation allows the derivation of few pars-per-million fluctuations in gas or humidity concentration. For validation purposes very first prototypes of resonator operating with whispering-gallery modes in the millimeter-wave frequency range are micro-machined. The obtained measured performances confirm that such high-Q resonant modes are very sensitive to small variations in dielectric resonator permittivity. Moreover we validate experimentally that these small variations can be remotely detected from the RADAR interrogation of an antenna loaded by the whispering-gallery modes resonator

Strategies for gas sensing by means of surface acoustic wave sensors

Support IFCPAR/CEFIPRAInternational audienceAs previously presented, Surface Acoustic Wave or SAW-based devices are of great interest for gas sensing applications. The major advantages related to the transducer itself, such as high sensitivity and real-time capability, are emphasized by appropriate strategies in defining the sensitive coating, which plays a major role in terms of sensitivity, selectivity and stability of the resulting device, including reversibility.In order to illustrate these issues, different strategies involved in various applications studied at IMS labs are presented. In particular, we will focus on grafted fluoropolyol matrices used for the detection of organophosphorous compounds, as well as on structured thin-film materials emphasized for their high effective surface among other advantages, such as mesoporous silicon dioxide or titania. We will also introduce an increasing interest for carbonated materials such as nanotubes or graphene which could lead to unexpected sensitivities, for SAW microsensors and more generally for microtransducers based on high frequency resonant phenomenon