Search results for "electronics"
showing 10 items of 4340 documents
Acoustic Topological Circuitry in Square and Rectangular Phononic Crystals
2021
International audience; We systematically engineer a series of square and rectangular phononic crystals to create experimental realizations of complex topological phononic circuits. The exotic topological transport observed is wholly reliant upon the underlying structure which must belong to either a square or rectangular lattice system and not to any hexagonal-based structure. The phononic system chosen consists of a periodic array of square steel bars which partitions acoustic waves in water over a broadband range of frequencies (∼0.5MHz). An ultrasonic transducer launches an acoustic pulse which propagates along a domain wall, before encountering a nodal point, from which the acoustic si…
Target 5G visible light positioning signal subcarrier extraction method using particle swarm optimization algorithm
2021
International audience; With the explosive growth of demand for Internet of Things (IoT) applications and the increasing dependence of users on wireless connections, indoor location based service(LBS) under 5G-Public-Private Partnership (5G-PPP) using cases have received more attention and get rapid development. Thanks to the safty, security and customization of 5G network pointed by 5G forum white paper, indoor positioning systems using unified 5G New Radio (NR) signals have become the focus of the next generation of visible light positioning (VLP) systems. In 5G New Radio(NR) frame, totally 192 subcarriers are used to carry positioning reference signal(PRS). In order to improve the positi…
Surface plasmon interference excited by tightly focused laser beams
2007
International audience; We show that interfering surface plasmon polaritons can be excited with a focused laser beam at normal incidence to a plane metal film. No protrusions or holes are needed in this excitation scheme. Depending on the axial position of the focus, the intensity distribution on the metal surface is either dominated by interferences between counterpropagating plasmons or by a two-lobe pattern characteristic of localized surface plasmon excitation. Our experiments can be accurately explained by use of the angular spectrum representation and provide a simple means for locally exciting standing surface plasmon polaritons.
Cavity Resonator Integrated Guided mode resonance Filter : Spectral & Modal Reflector
2015
International audience; CRIGF is a new generation of narrowband filter. It consists of subwavelength gratings nearby or upon a waveguide. At the center, a small GMRF (Guided Mode Resonance Filter) or GC (Grating Coupler) coupled radiated & guided mode, then, DBR (Distributed Bragg Reflector) at each side localise mode inside a horizontal Fabry-Pérot cavity. Two PS (Phase sections) are use to fine tune the Fabry-Pérot modes with the grating coupler.
VUV photofragmentation of protonated leucine-enkephalin peptide: partial ion yield dependence on type of sequence fragments
2013
International audience
On improving the accuracy of Visible Light Positioning system based PAPR reduction schemes
2020
International audience; DC-biased optical Orthogonal Frequency Division Multiplexing (DCO-OFDM)-based visible light positioning (VLP) technology along with the Received Signal Strength(RSS) positioning algorithm is widely used to achieve centimeter level positioning accuracy for incoming 5G era, especially indoor environment. However, the DCO-OFDM has the peak-to-average power ratio (PAPR) issue which imposes the nonlinear distortion and it will directly affect the positioning accuracy in the VLP system. The PAPR reduction scheme is urgently needed. Therefore , in this paper, the impact of PAPR reduction scheme on positioning accuracy is investigated. The positioning accuracy with and witho…
Gas sensors arrays (electronic noses) : a study about the speed/accuracy ratio
2000
Abstract New Fingerprint Mass Spectra (FMS) systems claim for a higher precision, a reduced analysis time, and a lower drift, compared with Gas Sensors Arrays ‘Electronic Noses’. We demonstrated in this study that metal oxide gas sensors may have highly improved performances for both accuracy and run time, when used in optimum conditions. The different noise components were quantified referring to popular words (equivalent of ethanol concentration) using the transfer function of the sensor. It was pointed out that sample surrounding greatly affects the noise level, and that the signal-to-noise ratio may be dramatically increased, reducing the distortion generally assessed between sensor and…
Microstructuration des dépôts imprimés par jet d'encre de la coalescence des nanoparticules d'argent vers la réalisation d'interconnexions de composa…
2012
Several challenges are still holding back the technological transfer of printed electronics to industry in spite of recent progresses. In this thesis work, the printing method of inks based on silver nanoparticles (=25 nm) was optimized according to its rheology and to the fluid/substrate interactions for the fabrication of electrical interconnections with a thickness of 500 nm. These lines were printed on silicon or flexible substrates and annealed either by conventional (oven or infrared) or selective methods (microwave) at temperatures comprised between 100 and 300 °C.A better understanding of the relationship between process and microstructure of these printed thin films, based on sever…
P-Type Doping of 4H-SiC for Integrated Bipolar and Unipolar Devices
2015
International audience; P-type 4H-SiC layers formed by ion implantation need high temperature processes, which generate surface roughness, losing and incomplete activation of dopants. Due to dopant redistribution and channeling effect, it is difficult to predict the depth of the formed junctions. Vapor-Liquid-Solid (VLS) selective epitaxy is an alternative method to obtain locally highly doped p-type layers in the 1020 cm-3 range or more. The depth of this p-type layers or regions is accurately controlled by the initial Reactive-Ion-Etching (RIE) of the SiC. Lateral Junction Field Effect Transistor (JFET) devices are fabricated by integrating p-type layers created by Al ion implantation or …
Functionnalized Surface Acoustic Wave Sensors for the Detection of Hazardous Gases
2018
International audience; In this work, we show the capabilities of Surface Acoustic Wave (SAW) devices to probe the properties of gas sensitive materials for the manufacturing of hazardous gas sensors. The great capabilities of cobalt corroles for the trapping of carbon monoxide (CO) were exploited to produce selective sensors. These corroles were deposited on SAW delay lines surfaces and then exposed to carbon monoxide (CO) in standard conditions. Concentrations of a few hundreds of ppb were measured emphasizing the interest of such sensors for the detection of CO. Another type of sensitive layers exhibiting specific porosity adapted to the trapping of formaldehyde (CH$_2$O) were deposited …