Développement des capteurs sans fil basés sur les tags RFID uhf passifs pour la détection de la qualité des aliments

Le but de cette thèse est de développer des capteurs sur la base des tags RFID, des technologies et matériaux disponibles au Vietnam afin de contribuer à résoudre la problématique du contrôle de la qualité des produits alimentaires. En effet la technologie RFID s est affirmée en importance pour ses applications dans de nombreux domaines. Dans ce contexte, l identification des produits alimentaires expirés, sans les endommager, est une orientation de recherche très prometteuse. Un tag RFID UHF passif peut aussi être composé de plusieurs puces et plusieurs antennes, chaque couple puce/antenne conçu pour travailler sur un intervalle déterminé de valeur de permittivité. Donc, à partir de l ensemble des permittivités définies pour chaque couple puce/antenne et les signaux réfléchis vers le lecteur, nous pourrons mesurer la permittivité de l objet tracé. Ainsi la connaissance de la permittivité des aliments et la conception spécifique de l antenne, nous développerons un tag capteur de type "multi puce/antenne" qui sera utilisé comme un capteur sans fil pour la détection de la qualité des alimentsIn recent years, RFID technology has established itself in importance, particularly for applications in the civil sector. In this context, identification of expired products without damage is a very promising direction of research. However, the price of these sensors is still too high especially compared to living in Vietnam. A passive UHF RFID tag chip can include many antennae and many chips on a same substrate in which each pair of chip/antenna is designed to be activated on a determined interval value of permittivity. So from designed permittivities for each pair of chip/antenna and the reflected signals to the reader, we can define the value of permittivity of the object that is labelled with RFID tag. From the characterization of food permittivity and the background of antenna design, we developped a sensor tag "multi chip/antenna" to be used as a wireless sensor for the detection of food quality. The aim of this thesis intends to develop a new family of wireless sensors based on RFID technology and available technology of fabrication in Vietnam to solve this problem.SAVOIE-SCD - Bib.électronique (730659901) / SudocGRENOBLE1/INP-Bib.électronique (384210012) / SudocGRENOBLE2/3-Bib.électronique (384219901) / SudocSudocFranceF

Control of crystalline volume and nano crystal grain size in nanocrystalline silicon thin film deposited by PECVD

Application of the radio frequency plasma enhanced chemical vapor deposition (RF-PECVD) technique was studied to fabricate amorphous and nanocrystalline silicon (a-Si and nc-Si) thin films for photovoltaic devices at substrate temperature of 200 °C. Amorphous-crystalline transition of silicon thin films in working conditions of PECVD system was shown as a function of deposition parameters, i.e., dilution ratio of silane (SiH4) in hydrogen, total gas pressure during deposition and RF excitation power density. The crystalline volume as well as grain size of nanocrystalline silicon films could be successfully controlled by tuning those deposition parameters. Micro Raman scattering spectroscopy and spectroscopic ellipsometry (SE) methods were used to characterize the structure and crystallization of the deposited silicon thin films. We could make nc-Si thin films with various crystalline volumes. Nc-Si grain size was also controlled and was in the range of 3–5 nm

Gold nanoparticles created by rapid thermal annealing process applied to thin film solar cell

In this work, the formation of gold nanoparticles (Au NPs) was studied. A gold thin film was first deposited by E-beam Evaporation method followed by rapid thermal annealing (RTA) to create nanoparticles with many different sizes and shapes. The localized surface plasmon resonance (LSPR) effect was also determined. By proper engineering of these metallo-dielectric structures, light can be concentrated and “folded” into a thin semiconductor layer, thereby the absorption can be increased. This approach provides a new development for improving light trapping in thin-film solar cells (TFSCs)

Molecular Dynamics Simulation from Symmetry Breaking Changing to Asymmetrical Phospholipid Membranes Due to Variable Capacitors during Resonance with Helical Proteins

Biological symmetry breaking is a mechanism in biosystems that is necessary for human survival, and depends on chemical physics concepts at both microscopic and macroscopic scales. In this work, we present a few mechanisms of the signaling phenomenon that have been studied in various tissues of human origin. We exhibit that anatomical asymmetry in the structure of a membrane can produce a flow of extracellular fluid. Furthermore, we exhibit that membrane asymmetry is a misbalance in the composition of the aqueous phases and interaction forces with the protein trans-membrane. Various biological membranes such as DPPC, DMPC, DLPC, and so on, have considerable electrostatic voltages that extend across the phosphor lipids bilayer. For studying these phenomena, we modeled DPPC, DMPC, and DLPC lipid bilayers with a net charge misbalance across the phospholipids. Because asymmetric membranes create the shifted voltages among the various aqueous tissues, this effect makes the charge misbalances cause a voltage of 1.3 V across the DPPC bilayer and 0.8 V across the DMPC bilayer. This subject exhibits the importance of membrane structures on electrostatic potential gradients. Finally, we exhibited that a quantum effect was created in small parts of the cell’s thickness due to the symmetry breaking of asymmetrical phospholipid bilayers

Novel design of RFID UHF passive tag for wideband applications by direct and contactless chip connection

International audienceIn this paper, we present two different designs for Ultra High Frequency (UHF) Radio Frequency Identification (RFID) passive tags. The first proposed design has been mounted on AK3 Tagsys® loop, which is a small loop antenna already connected to the chip while the second approach is connected directly with RFID chip. The optimized designs have compact size and bandwidth for worldwide UHF RFID applications (860MHz to 960 MHz). The advantages and disadvantages of each approach will be also discussed. From the experimental results, these designs have the acceptable read-range for ETSI regulations of RFID (9.6m and 5.97m) and can be applied for real-world applications. However, the calibration between the simulation and the characterization in order to remove the tolerance of fabrication process should be executed in future steps to obtain the best performance by improving the proposed designs

Approach for quality detection of food by RFID-based wireless sensor tag

International audienceA novel wireless sensor for the detection of food quality is presented. The main idea is to transform radio frequency identification (RFID) tags into RFID sensors, owing to a specific design of the tag antenna. From knowledge of the variation of the permittivity of food over time through experimental characterisation, it is possible to detect the time from which the food becomes improper for consumption based on the read-range measurement of the designed sensing tags. This low-cost ultra-high frequency (UHF) RFID passive sensor was designed and experimentally tested on plastic-film-wrapped beef meat. The overall agreement between the experimental and simulation results shows the potential of this technique for real-world applications in food traceability

RFID beefs up

International audienceA low-cost wireless sensor for the real-time detection of food contamination and quality has been developed by collaborating researchers from the Vietnam National University, and CEA-LETI and Université Grenoble Alpes in France. In their approach, RFID passive tags are transformed into sensors that show potential to create a non-invasive, robust and cheap alternative that could be used by small companies and individuals in the food industry and agriculture