Hamida Hallil

Wireless sensing and identification of passive electromagnetic sensors based on millimetre-wave FMCW RADAR

The wireless measurement of various physical quantities from the analysis of the RADAR Cross Sections variability of passive electromagnetic sensors is presented. A millimetre-wave Frequency-Modulated Continuous-Wave RADAR is used for both remote sensing and wireless identification of sensors. Long reading ranges (up to some decameters) may be reached at the expense of poor measurement resolution (typically 10%).

Inkjet-Printed Graphene Oxide Thin Layers on Love Wave Devices for Humidity and Vapor Detection

We report inkjet printing as an alternative deposition method for low-cost gas or humidity sensors based on graphene oxide (GO)-coated Love wave devices. Our inkjet printing method paves the way toward massive, large-area industrial production of multi-layered GO chemical sensing films for volatile organic compounds and relative humidity (RH) detection applications. The adsorption of vapor compounds on GO led to the sensitivities of 30 Hz/ppm, 24 Hz/ppm, and 2.4 kHz/1% of ethanol (C2H6O), toluene (C7H8), and RH, respectively. Electrical, gaseous, and RH characterization analyses showed that this GO-based inkjet printing method is one of the most promising features for inexpensive and high-speed patterning devices for high demanding gas trace or RH sensing applications.

Novel SH-SAW gas sensor based on graphene

In this article, a novel gas sensor platform has been studied. Several layers of graphene have been deposited on a SH-SAW, as a sensitive layer. Innovative methods of graphene solutions have been prepared in order to explore gas sensing applications. The real time detection measurement of the coated sensor under ethanol and humidity is presented. The adsorption of vapors leads to a frequency shift of 10.5 kHz and 22.7 kHz, at exposure of 100 ppm of ethanol and 6.22% of Relative Humidity, respectively. The experiments have been realized at room temperature; rapid response and recovery time were observed.

Capacitive microwave resonator printed on a paper substrate for CNT based gas sensor

Inkjet-printed RF electronics fabricated on paper and other flexible substrates are introduced as a low-cost solution for the sensor applications. Inkjet printing is an additive process that has enabled various disruptive technologies combining new materials with novel multidisciplinary operation concepts. This paper presents a fully inkjet printed capacitive structure used to provide a differential detection, by comparing the frequency responses of quasi-twin structures, one with and one without sensitive material. The sensitive surface is printed with a polymer solution containing multi-wall carbon nanotubes (CNTs), and the resonator is dimensioned for operating in the RF band.

Using Microsensors to Promote Development of Innovative Therapeutic Nanostructures

Compared to analytical labs requiring large instruments and skilled users, micro/nano-sensors show great promise as convenient economic tools for specific detection based on bio-physico-chemical interactions of target compounds on sensitive coatings, and for monitoring dynamically the characteristics of fluids or biofilms, as influenced by new compounds. We present an overview of the existing microsensors, and their principles, and describe microsensors that can be developed for fast evaluation of efficiency and toxicity of innovative therapeutic nanostructures. We also describe their key applications, and discuss the analytical techniques employed. Integrative technologies involving multisensor set - akin to an electronic nose or tongue, or those involving a separator step prior to the transducer itself are also presented. Specifically, we discuss micro/nano-fluidics with relevance to particule-flow management, in the field of microsensors towards therapeutics. Ex vivo and in vivo approaches are considered, both in-line or remote controlled, with various analytes collected using invasive or non-invasive techniques.

Inkjet — Printed graphene layer by layer on SAW devices for gas detection applications

This work demonstrates ink-jet printing as an alternative deposition method for low cost gas sensors based on graphene. Our ink-jet printing method paves the way towards for massive, large-area industrial production of Graphene Oxide (GO) multilayer sensitive films for Volatile Organic Compounds (VOCs) detection. The adsorption of vapor compounds on GO leads to a sensitivity of 30 Hz/ppm and 24 Hz/ppm of C2H6O and C7H8, respectively. The experiments were conducted in real-time under ambient conditions, which places this layer-by-layer inkjet printing technique one of the most promising features for inexpensive and high-speed patterning deposition method for trace-gas applications.