Ludivine Fadel - Academia.edu (original) (raw)

Papers by Ludivine Fadel

Research paper thumbnail of Mass sensitivity measurement of chemical resonant microcantilever sensors

Research paper thumbnail of Microbalances résonantes en silicium pour mesures (bio) chimiques

Research paper thumbnail of A dual band 915MHz/2.44GHz RF energy harvester

2015 European Microwave Conference (EuMC), 2015

Research paper thumbnail of Coupled determination of gravimetric and viscoelastic effects on two resonant chemical sensors: love-wave and microcantilever platforms

Research paper thumbnail of Microcantilever: a chemical resonant sensor

Silicon micromachined cantilevers can be used as chemical resonant sensor by adding a sensitive l... more Silicon micromachined cantilevers can be used as chemical resonant sensor by adding a sensitive layer on the device structure. In this paper, the process technology, based on the use of SOI wafer, and the sensitive layer deposition are described. Using four different geometrical microcantilevers, the frequency dependence to mass modification is measured and allows to predict gas sensor response.

Research paper thumbnail of Microcapteurs chimiques à structures mobiles pour la détection d'espèces gazeuses

L'utilisation de couches sensibles déposées sur des microstructures vibrantes permet la réalisati... more L'utilisation de couches sensibles déposées sur des microstructures vibrantes permet la réalisation de capteurs chimiques à très haute sensibilité. En mesurant la fréquence de résonance de ces structures, il est possible de déterminer les variations de masse liées à la présence de substances gazeuses adsorbées par la couche sensible. Dans cet article, le principe physique et la technologie d'élaboration de telles microstructures vibrantes sont d'abord présentés. Ensuite, à partir de mesures de détection de vapeur d'éthanol, l'influence de la fréquence de résonance et de l'épaisseur de la couche sensible sur les performances du capteur (sensibilité, limite de détection, temps de réponse) sont étudiées. ABSTRACT. The use of sensitive coating deposited on resonant microstructures enables to achieve high sensitivity chemical sensors. By measuring their resonant frequency, mass variations can be determined in order to deduce gaseous substances sorbed by the sensitive coating. In this paper, the physical and technological principles of such resonant microstructures are depicted. Then, based on vapour ethanol detections, the influence of the resonant frequency and sensitive coating thickness on the sensor performances (sensitivity, limit of detection, time response) are studied. MOTS-CLÉS : Capteur chimique, micropoutre, fréquence de résonance, détection de gaz, microsystèmes.

Research paper thumbnail of Vers l’électronique imprimée à l’IMS Bordeaux - plateforme technologique TAMIS (Technologies Alternatives aux MIcrosystèmes Silicium)

Research paper thumbnail of Microcapteurs à structures mobiles pour la détection d'espèces gazeuses

Research paper thumbnail of Mass sensitivity measurement of chemical resonant microcantilever sensors

Research paper thumbnail of Preprint-203rd Meeting of the Electrochemical Society, Paris, France, 27 April-2 May 2003

Research paper thumbnail of A 900MHz RF energy harvesting module

10th IEEE International NEWCAS Conference, 2012

ABSTRACT This paper presents a guideline to design and optimize a RF energy harvester operating i... more ABSTRACT This paper presents a guideline to design and optimize a RF energy harvester operating in ISM Band at 902 MHz. The circuit is implemented on a standard FR4 board with commercially available off-the-shelf devices. The topology of the impedance transformation block is selected to reduce the losses which improves the overall performances of the system. The characterization of the harvesting module shows sensitivity of -22.5 dBm for a dc output voltage of 200 mV up to -11 dBm for 1.08 V. A wireless power transmission in an indoor environment is measured with a radiated source power of 16.8 dBm. The harvester exhibits a DC rectified voltage of 1.25 V at 0.5 meter and still 500 mV at 1.5 meter.

Research paper thumbnail of Silicon made resonant microcantilever: Dependence of the chemical sensing performances on the sensitive coating thickness

Materials Science and Engineering: C, 2006

A gas sensor based on the use of a resonating microcantilever has been realized by using a polyme... more A gas sensor based on the use of a resonating microcantilever has been realized by using a polymer sensitive coating. From the theoretical study of the microcantilever sensitivity, it has been deduced that the sensitivity is enhanced when the resonant frequency or the sensitive coating thickness are increased. The sensitive coating thickness influence has then been verified experimentally by using PEUT (polyetherurethane) as sensitive coating for ethanol detection. From these measurements, some drawbacks are shown: the coating thickness increase leads to a sensor response time increase and a frequency noise increase which worsens the limit of detection. Conclusions are then made about the sensitive coating optimization depending on application constraint considerations.

Research paper thumbnail of Chemical sensing: millimeter size resonant microcantilever performance

Journal of Micromechanics and Microengineering, 2004

Based on the use of resonant cantilever, a mass sensitive gas sensor for the detection of Volatil... more Based on the use of resonant cantilever, a mass sensitive gas sensor for the detection of Volatile Organic Compounds (VOC) has been developed. Analyte gases are absorbed by a sensitive layer deposited on cantilever: the resulting mass change of the system implies the cantilever resonant frequency decrease. In this paper, the process technology, based on the use of SOI wafer, is described. To integrate the measurement, piezoelectric and electromagnetic excitations are investigated and for the detection of microcantilever vibrations, piezoresistive measurement is performed. Then, the polymer choice and the spray coating system are detailed. Using various geometrical microcantilevers, the frequency dependence to mass change is measured and allows to estimate the mass sensitivity (0.06Hz/ng). In gas detection the first experiments exhibit the sensor response, then by calculating the partition coefficient (K=977), the minimum detectable concentration of ethanol is deduced and permits to estimate the gas sensor resolution (14 ppm).Finally a comparison between millimeter size and micrometer size cantilever shows the importance of noise in the design of an integrated sensor.

Research paper thumbnail of Coupled determination of gravimetric and elastic effects on two resonant chemical sensors: Love wave and microcantilever platforms

IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 2000

The field of chemical microsensors for both gas and liquid sensing has been widely investigated i... more The field of chemical microsensors for both gas and liquid sensing has been widely investigated in recent years. Several technologies have been utilized which include Love-wave acoustic sensors and silicon microcantilevers. Those structures are both used as chemical sensors by adding a sensitive coating to the device surface. Perturbations of the sensitive coating properties induce frequency drift in both devices, thus making chemical detection possible. Microcantilevers are essentially sensitive to the coating mass changes which modify the resonant frequency of the structure. However, the acoustic wave device is sensitive to all types of propagation perturbations which include mass loading and mechanical properties changes of the coating. One of the difficulties in acoustic sensor field is to separate each contribution from the induced frequency shifts. The aim of this paper is to couple experimental results from microcantilevers and Love-wave devices in order to identify and separate the two effects. At last, this coupled study is also interesting for gas and liquid phase detection applications, as it will permit to determine the elasticity evolution during the detection process, i.e. the analyte sorption.

Research paper thumbnail of Analytical modeling of microcantilever and microbridge type chemical sensors: optimisation of the gravimetric sensitivity

An alternative to traditional chemical microsensors without moving part is the use of microcantil... more An alternative to traditional chemical microsensors without moving part is the use of microcantilevers whose interest lies primarily in their great sensitivity and their compactness. The effect used by this type of sensor is based on the modification of the mechanical properties of a microcantilever. These modifications are obtained by depositing a sensitive layer on the microstructure: the sorption of specific species by this material modifies its physicochemical characteristics and consequently the mechanical properties of the structure. The principal modification used within the framework of chemical sensors are the variation of the resonance frequency due to the mass modification of the system or the bending variation because of the mechanical stress difference between the microcantilever and the sensitive layer after sorption.

Research paper thumbnail of Poutres résonantes en silicium pour détection chimique

Research paper thumbnail of High order modes to improve sensitivity of resonant microcantilever chemical microsensors

By measuring shifts in the resonant frequencies of silicon microcantilevers coated with sensitive... more By measuring shifts in the resonant frequencies of silicon microcantilevers coated with sensitive layer, it is possible to obtain competitive chemical microsensors. In fact the sensitivity of such microsensor is improved with high resonant frequency device. Usually, in order to obtain high resonant frequency, small microcantilevers are used. The increase limitation of the natural frequency by reducing the microstructure size is often due to a limitation of the deflection measurement principle. Furthermore, it could be also difficult to obtain reproducible sensitive coating on very small surfaces. In order to achieve high sensitivities corresponding to high frequencies, without decreasing the microstructure size, high order flexural modes can be considered. In this paper, it is demonstrated that theoretically the performance of the resonant microcantilever chemical sensors is essentially due to the resonant frequency value and not of the mode order.

Research paper thumbnail of Optimization of the signal to noise ratio of resonant microcantilever type chemical sensors

TRANSDUCERS '03. 12th International Conference on Solid-State Sensors, Actuators and Microsystems. Digest of Technical Papers (Cat. No.03TH8664), 2000

Resonant microstructures can be used as chemical microsensors, by adding a sensitive coating to t... more Resonant microstructures can be used as chemical microsensors, by adding a sensitive coating to the device structure. Those vibrating structures are sensitive to the coating mass changes which modify the natural resonant frequency. The sensitivity, key parameter of such sensor, is proportional to the resonant frequency. But, if detection method consists in frequency measurement with a ring oscillator, the noise signal must be taken into account. A large study of these reflections, combined with a signal to noise ratio optimization, leads us to maximize quality factor to microstructure thickness ratio.

Research paper thumbnail of Mass sensitivity measurement of chemical resonant microcantilever sensors

Research paper thumbnail of Microbalances résonantes en silicium pour mesures (bio) chimiques

Research paper thumbnail of A dual band 915MHz/2.44GHz RF energy harvester

2015 European Microwave Conference (EuMC), 2015

Research paper thumbnail of Coupled determination of gravimetric and viscoelastic effects on two resonant chemical sensors: love-wave and microcantilever platforms

Research paper thumbnail of Microcantilever: a chemical resonant sensor

Silicon micromachined cantilevers can be used as chemical resonant sensor by adding a sensitive l... more Silicon micromachined cantilevers can be used as chemical resonant sensor by adding a sensitive layer on the device structure. In this paper, the process technology, based on the use of SOI wafer, and the sensitive layer deposition are described. Using four different geometrical microcantilevers, the frequency dependence to mass modification is measured and allows to predict gas sensor response.

Research paper thumbnail of Microcapteurs chimiques à structures mobiles pour la détection d'espèces gazeuses

L'utilisation de couches sensibles déposées sur des microstructures vibrantes permet la réalisati... more L'utilisation de couches sensibles déposées sur des microstructures vibrantes permet la réalisation de capteurs chimiques à très haute sensibilité. En mesurant la fréquence de résonance de ces structures, il est possible de déterminer les variations de masse liées à la présence de substances gazeuses adsorbées par la couche sensible. Dans cet article, le principe physique et la technologie d'élaboration de telles microstructures vibrantes sont d'abord présentés. Ensuite, à partir de mesures de détection de vapeur d'éthanol, l'influence de la fréquence de résonance et de l'épaisseur de la couche sensible sur les performances du capteur (sensibilité, limite de détection, temps de réponse) sont étudiées. ABSTRACT. The use of sensitive coating deposited on resonant microstructures enables to achieve high sensitivity chemical sensors. By measuring their resonant frequency, mass variations can be determined in order to deduce gaseous substances sorbed by the sensitive coating. In this paper, the physical and technological principles of such resonant microstructures are depicted. Then, based on vapour ethanol detections, the influence of the resonant frequency and sensitive coating thickness on the sensor performances (sensitivity, limit of detection, time response) are studied. MOTS-CLÉS : Capteur chimique, micropoutre, fréquence de résonance, détection de gaz, microsystèmes.

Research paper thumbnail of Vers l’électronique imprimée à l’IMS Bordeaux - plateforme technologique TAMIS (Technologies Alternatives aux MIcrosystèmes Silicium)

Research paper thumbnail of Microcapteurs à structures mobiles pour la détection d'espèces gazeuses

Research paper thumbnail of Mass sensitivity measurement of chemical resonant microcantilever sensors

Research paper thumbnail of Preprint-203rd Meeting of the Electrochemical Society, Paris, France, 27 April-2 May 2003

Research paper thumbnail of A 900MHz RF energy harvesting module

10th IEEE International NEWCAS Conference, 2012

ABSTRACT This paper presents a guideline to design and optimize a RF energy harvester operating i... more ABSTRACT This paper presents a guideline to design and optimize a RF energy harvester operating in ISM Band at 902 MHz. The circuit is implemented on a standard FR4 board with commercially available off-the-shelf devices. The topology of the impedance transformation block is selected to reduce the losses which improves the overall performances of the system. The characterization of the harvesting module shows sensitivity of -22.5 dBm for a dc output voltage of 200 mV up to -11 dBm for 1.08 V. A wireless power transmission in an indoor environment is measured with a radiated source power of 16.8 dBm. The harvester exhibits a DC rectified voltage of 1.25 V at 0.5 meter and still 500 mV at 1.5 meter.

Research paper thumbnail of Silicon made resonant microcantilever: Dependence of the chemical sensing performances on the sensitive coating thickness

Materials Science and Engineering: C, 2006

A gas sensor based on the use of a resonating microcantilever has been realized by using a polyme... more A gas sensor based on the use of a resonating microcantilever has been realized by using a polymer sensitive coating. From the theoretical study of the microcantilever sensitivity, it has been deduced that the sensitivity is enhanced when the resonant frequency or the sensitive coating thickness are increased. The sensitive coating thickness influence has then been verified experimentally by using PEUT (polyetherurethane) as sensitive coating for ethanol detection. From these measurements, some drawbacks are shown: the coating thickness increase leads to a sensor response time increase and a frequency noise increase which worsens the limit of detection. Conclusions are then made about the sensitive coating optimization depending on application constraint considerations.

Research paper thumbnail of Chemical sensing: millimeter size resonant microcantilever performance

Journal of Micromechanics and Microengineering, 2004

Based on the use of resonant cantilever, a mass sensitive gas sensor for the detection of Volatil... more Based on the use of resonant cantilever, a mass sensitive gas sensor for the detection of Volatile Organic Compounds (VOC) has been developed. Analyte gases are absorbed by a sensitive layer deposited on cantilever: the resulting mass change of the system implies the cantilever resonant frequency decrease. In this paper, the process technology, based on the use of SOI wafer, is described. To integrate the measurement, piezoelectric and electromagnetic excitations are investigated and for the detection of microcantilever vibrations, piezoresistive measurement is performed. Then, the polymer choice and the spray coating system are detailed. Using various geometrical microcantilevers, the frequency dependence to mass change is measured and allows to estimate the mass sensitivity (0.06Hz/ng). In gas detection the first experiments exhibit the sensor response, then by calculating the partition coefficient (K=977), the minimum detectable concentration of ethanol is deduced and permits to estimate the gas sensor resolution (14 ppm).Finally a comparison between millimeter size and micrometer size cantilever shows the importance of noise in the design of an integrated sensor.

Research paper thumbnail of Coupled determination of gravimetric and elastic effects on two resonant chemical sensors: Love wave and microcantilever platforms

IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 2000

The field of chemical microsensors for both gas and liquid sensing has been widely investigated i... more The field of chemical microsensors for both gas and liquid sensing has been widely investigated in recent years. Several technologies have been utilized which include Love-wave acoustic sensors and silicon microcantilevers. Those structures are both used as chemical sensors by adding a sensitive coating to the device surface. Perturbations of the sensitive coating properties induce frequency drift in both devices, thus making chemical detection possible. Microcantilevers are essentially sensitive to the coating mass changes which modify the resonant frequency of the structure. However, the acoustic wave device is sensitive to all types of propagation perturbations which include mass loading and mechanical properties changes of the coating. One of the difficulties in acoustic sensor field is to separate each contribution from the induced frequency shifts. The aim of this paper is to couple experimental results from microcantilevers and Love-wave devices in order to identify and separate the two effects. At last, this coupled study is also interesting for gas and liquid phase detection applications, as it will permit to determine the elasticity evolution during the detection process, i.e. the analyte sorption.

Research paper thumbnail of Analytical modeling of microcantilever and microbridge type chemical sensors: optimisation of the gravimetric sensitivity

An alternative to traditional chemical microsensors without moving part is the use of microcantil... more An alternative to traditional chemical microsensors without moving part is the use of microcantilevers whose interest lies primarily in their great sensitivity and their compactness. The effect used by this type of sensor is based on the modification of the mechanical properties of a microcantilever. These modifications are obtained by depositing a sensitive layer on the microstructure: the sorption of specific species by this material modifies its physicochemical characteristics and consequently the mechanical properties of the structure. The principal modification used within the framework of chemical sensors are the variation of the resonance frequency due to the mass modification of the system or the bending variation because of the mechanical stress difference between the microcantilever and the sensitive layer after sorption.

Research paper thumbnail of Poutres résonantes en silicium pour détection chimique

Research paper thumbnail of High order modes to improve sensitivity of resonant microcantilever chemical microsensors

By measuring shifts in the resonant frequencies of silicon microcantilevers coated with sensitive... more By measuring shifts in the resonant frequencies of silicon microcantilevers coated with sensitive layer, it is possible to obtain competitive chemical microsensors. In fact the sensitivity of such microsensor is improved with high resonant frequency device. Usually, in order to obtain high resonant frequency, small microcantilevers are used. The increase limitation of the natural frequency by reducing the microstructure size is often due to a limitation of the deflection measurement principle. Furthermore, it could be also difficult to obtain reproducible sensitive coating on very small surfaces. In order to achieve high sensitivities corresponding to high frequencies, without decreasing the microstructure size, high order flexural modes can be considered. In this paper, it is demonstrated that theoretically the performance of the resonant microcantilever chemical sensors is essentially due to the resonant frequency value and not of the mode order.

Research paper thumbnail of Optimization of the signal to noise ratio of resonant microcantilever type chemical sensors

TRANSDUCERS '03. 12th International Conference on Solid-State Sensors, Actuators and Microsystems. Digest of Technical Papers (Cat. No.03TH8664), 2000

Resonant microstructures can be used as chemical microsensors, by adding a sensitive coating to t... more Resonant microstructures can be used as chemical microsensors, by adding a sensitive coating to the device structure. Those vibrating structures are sensitive to the coating mass changes which modify the natural resonant frequency. The sensitivity, key parameter of such sensor, is proportional to the resonant frequency. But, if detection method consists in frequency measurement with a ring oscillator, the noise signal must be taken into account. A large study of these reflections, combined with a signal to noise ratio optimization, leads us to maximize quality factor to microstructure thickness ratio.