227 research outputs found
Modeling of a compact, implantable, dual-band antenna for biomedical applications
Different implantable antenna designs exist to establish communication with implantable devices depending on the domain of use and the implantation space. Owing to their nature and purposes, these antennas have many imposed criteria on various characteristics, such as bandwidth, multiband behavior, radiation pattern, gain, and specific absorption rate (SAR). This presents a challenge when it comes to achieving satisfying results without a major compromise in any of these crucial parameters. Additionally, many of the existing designs do not follow a specific approach to obtain results. Measuring different parameters of such fabricated structures requires special conditions and special environments mimicking the tissues where they are supposed to be placed. For such issues, the use of biological or synthetic phantoms is widely employed to validate what is obtained in simulation, and a multitude of formulas exist for the creation of such phantoms, each with its advantages and drawbacks. In this paper, a miniature dual-band structure derived from the first iteration of the Koch fractal structure is designed to operate 2 mm below the skin in the arm of the human body, with the MICS (Medical Implant Communication System) and ISM (Industrial, Scientific, Medical) 2.4 GHz bands. The purposes of the design are to derive structures from commonly used shapes with certain behavior while maintaining miniaturization, and to easily design dual-band implantable antennas. More than one band is used to diversify uses, since bands such as the MICS band are mainly dedicated to telemetry. The structure is characterized not only by its low profile compared to various structures found in the literature with dimensions of 17.2 × 14.8 × 0.254 mm3, but also its ease of design, independent shifting of resonant frequencies, and the absence of the need for a matching circuit and a shorting pin (via) for miniaturization. It exhibits satisfying performance: bandwidths of 23 MHz in the MICS band and 190 and 70 MHz in the vicinity of the ISM 2.4 GHz band, and measured gain in the latter band of −18.66 and −17 dBi in the azimuth and elevation radiation patterns, respectively. To validate the antenna’s properties in a skin-mimicking environment, two simple phantom formulas found in the literature were explored and compared in order to identify the best option in terms of accuracy and ease of fabrication.The authors would like to thank Nicolas Corrao for his tremendous effortsthroughout the challenging fabrication process of the preliminary models at the HYPER platform,IMEP-LaHC, University of Grenoble Alpes. R. Silva would like to thank FCT for grant 2021.06819.BD.All individuals included in this section have consented to the acknowledgement
Conception et miniaturisation des antennes pour les tags et les lecteurs RFID UHF passifs pour la localisation des personnes et des objets
National audienceLa RFID UHF est en plein développement grâce notamment à l'essor des transpondeurs RFID passifs utilisant le principe de rétro modulation et permettant d'obtenir une étiquette RFID très faible coût. L'EPC Global, organisme international dirigeant le développement de standard pour l'identification électronique de produits, envisage donc le suivi unitaire des produits par RFID. Hors, hormis des problèmes d'ordre éthique qui pourraient s'opposer à un tel déploiement de tags RFID, une telle solution peut être envisageable économiquement seulement si le coût unitaire des transpondeurs arrive au dessous de 0,10 € et que la capacité de production mondiale de tag RFID atteint plusieurs centaines de millions d'unités par an. Pour atteindre ce but, la miniaturisation des tags pourraient jouer plusieurs rôles essentiels comme celui de permettre d'augmenter les cadences de production des antennes (donc de diminuer le coût unitaire d'un tag) tout en permettant une certaine discrétion au transpondeur RFID. Dans cette communication, la conception des antennes RFID ainsi qu'une revue sur les techniques de miniaturisation dont celle du repliement sont présentées avec une discussion sur les limites de la miniaturisation et ses implications en termes de performances
Prospects for Food Fermentation in South-East Asia, Topics From the Tropical Fermentation and Biotechnology Network at the End of the AsiFood Erasmus+Project
Fermentation has been used for centuries to produce food in South-East Asia and some foods of this region are famous in the whole world. However, in the twenty first century, issues like food safety and quality must be addressed in a world changing from local business to globalization. In Western countries, the answer to these questions has been made through hygienisation, generalization of the use of starters, specialization of agriculture and use of long-distance transportation. This may have resulted in a loss in the taste and typicity of the products, in an extensive use of antibiotics and other chemicals and eventually, in a loss in the confidence of consumers to the products. The challenges awaiting fermentation in South-East Asia are thus to improve safety and quality in a sustainable system producing tasty and typical fermented products and valorising by-products. At the end of the “AsiFood Erasmus+ project” (www.asifood.org), the goal of this paper is to present and discuss these challenges as addressed by the Tropical Fermentation Network, a group of researchers from universities, research centers and companies in Asia and Europe. This paper presents current actions and prospects on hygienic, environmental, sensorial and nutritional qualities of traditional fermented food including screening of functional bacteria and starters, food safety strategies, research for new antimicrobial compounds, development of more sustainable fermentations and valorisation of by-products. A specificity of this network is also the multidisciplinary approach dealing with microbiology, food, chemical, sensorial, and genetic analyses, biotechnology, food supply chain, consumers and ethnology
CST exhibition, European Microwave Week - EUMW2010, séminaire invité
International audienc
RF printed electronic devices using bio-sourced materials: risks and opportunities
International audienceLike other sciences and technologies, electronics today faces an enormous challenge due to the scarcity of non-renewable resources and the need to decrease greenhouse gas emissions in order to reduce the climate change. In this context, the search for alternative roadmaps at all stages of the life cycle of an electronic product is a major issue. Additive processes, bio-sourced or organic materials and recyclable substrates are examples of subjects that can be explored to progressively substitute high impacts materials and methods by eco-friendly ones. At the same time, these solutions have a number of shortcomings that must be overcome in order for them to become economically and technically credible. In the domain of radio frequency devices, paper printed antennas and filters, electromagnetic energy harvesting systems, sensors and displays can be designed. This article presents an overview of what has been undertaken in this field by our team for over ten years for the design, fabrication and test of antennas. These devices were tested in several real environments for different applications such as anti-counterfeiting
RF printed electronic devices using bio-sourced materials: risks and opportunities
International audienceLike other sciences and technologies, electronics today faces an enormous challenge due to the scarcity of non-renewable resources and the need to decrease greenhouse gas emissions in order to reduce the climate change. In this context, the search for alternative roadmaps at all stages of the life cycle of an electronic product is a major issue. Additive processes, bio-sourced or organic materials and recyclable substrates are examples of subjects that can be explored to progressively substitute high impacts materials and methods by eco-friendly ones. At the same time, these solutions have a number of shortcomings that must be overcome in order for them to become economically and technically credible. In the domain of radio frequency devices, paper printed antennas and filters, electromagnetic energy harvesting systems, sensors and displays can be designed. This article presents an overview of what has been undertaken in this field by our team for over ten years for the design, fabrication and test of antennas. These devices were tested in several real environments for different applications such as anti-counterfeiting
Extraction de la matrice-S des composants optiques monomodes
Conférence JNOG 2003, Valence (France)Nous étudions l'extraction des paramètres S-optiques pour les composants planaires monomodes. Ces paramètres seront ensuite intégré dans un outil de simulation de type circuit. L'exemple, présenté dans cette communication concerne la jonction « Y » dont tous les accès sont des guides monomodes. La simulation électromagnétique est réalisée grâce à la suite FEMLAB intégrée sous un environnement MatLa
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