136 research outputs found
Small Footprint Multilayered Millimeter-Wave Antennas and Feeding Networks for Multi-Dimensional Scanning and High-Density Integrated Systems
This paper overviews the state-of-the-art of substrate integrated waveguide (SIW) techniques in the design and realization of innovative low-cost, low-profile and low-loss (L3) millimeter-wave antenna elements, feeding networks and arrays for various wireless applications. Novel classes of multilayered antenna structures and systems are proposed and studied to exploit the vertical dimension of planar structures to overcome certain limita-tions in standard two-dimensional (2-D) topologies. The developed structures are based on two techniques, namely multi-layer stacked structures and E-plane corners. Differ-ent E-plane structures realised with SIW waveguide are presented, thereby demonstrating the potential of the proposed techniques as in multi-polarization antenna feeding. An array of 128 elements shows low SLL and height gain with just 200g of the total weight. Two versions of 2-D scanning multi-beam are presented, which effectively combine frequency scanning with beam forming networks. Adding the benefits of wide band performance to the multilayer structure, two bi-layer structures are investigated. Different stacked antennas and arrays are demonstrated to optimise the targeted antenna performances in the smallest footprint possible. These structures meet the requirement for developing inexpensive compact millimeter-wave antennas and antenna systems. Different structures and architectures are theoretically and experimentally studied and discussed for specific space- and ground-based appli-cations. Practical issues such as high-density integration and high-volume manufacturability are also addressed
Ătude et rĂ©alisation de matrices Ă commutation de faisceaux en technologie guide d'ondes intĂ©grĂ© au substrat
RĂSUMĂ Les applications radar pour les voitures demandent des composants de hautes performances mais avec faible coĂ»t de revient. Cette thĂšse prĂ©sente la conception des rĂ©seaux dâalimentation dâantennes en ondes millimĂ©triques utilisant la technologie du guide dâondes intĂ©grĂ© aux substrats (GIS), pour satisfaire les exigences du coĂ»t et du faible encombrement dans ces applications de radar.
Dans un systĂšme radar, lâantenne dĂ©fini la largeur du secteur couvert, la portĂ©e, la discrimination angulaire et le filtrage du bruit gĂ©nĂ©rĂ© par dâautre sources. GĂ©nĂ©ralement les antennes intelligentes remplissent ce cahier des charges. La direction dans laquelle le rĂ©seau ayant la rĂ©ponse maximale serait la direction du pointage de faisceau. Pour un choix de faisceau dans une direction dĂ©sirĂ©e, un ajustement de phase doit ĂȘtre accompli. Les matrices Ă commutation donnent des distributions de phase aux sorties diffĂ©rentes pour chaque port dâentrĂ©e.
Le guide dâondes intĂ©grĂ© aux substrats (GIS) offre une technologie intĂ©ressante pour les rĂ©seaux dâalimentation dâantennes en termes de faible pertes par radiation, ce qui assure un trĂšs faible niveau dâinterfĂ©rences et dâeffets parasitiques entre les circuits de GIS. Nous proposons dans ce travail plusieurs matrices de formation de faisceaux basĂ©es sur la technologie GIS. La thĂšse est prĂ©sentĂ©e sous forme dâarticles. Ce travail montre les Ă©tapes entreprises afin de mener Ă terme la conception, la fabrication, les mesures et lâĂ©valuation de plusieurs topologies de la matrice de Butler. Nous verrons donc dans un premier temps les composants nĂ©cessaires au bon fonctionnement dâun tel systĂšme soit: les coupleurs 3 dB, les dĂ©phaseurs et les croisements. Le choix de la configuration sera justifiĂ© pour chacun de ces Ă©lĂ©ments. Lâusage de simulateur (Ansoft HFSS) basĂ© sur la mĂ©thode des Ă©lĂ©ments finis (une mĂ©thode Ă ondes complĂštes) sera nĂ©cessaire dans ce travail. Ce logiciel donne des rĂ©sultats assez proches des essais expĂ©rimentaux. Trois matrices de Butler sont dĂ©veloppĂ©es, la premiĂšre Ă 77 GHz sans croisement, une deuxiĂšme est une structure Ă deux couches Ă 24 GHz et la troisiĂšme est une matrice complĂštement planaire avec un coupler 0 dB Ă 12.5 GHz.----------
ABSTRACT Automotive radar applications require components with high performance but low cost. This thesis presents the design of millimeter wave antennas feeding networks using the substrate integrated waveguide (SIW) technology, to satisfy the requirement of low cost and compactness in these radar applications.In a radar system the antenna define the width of covered area, the range, the angular discrimination and the filter noise generated by other sources. Generally smart antennas must be used to satisfy the specifications. The beam pointing can be achieved only by adjusting the phase of signals from different elements. For a choice of beam in a desired direction, a phase adjustment must be done. Switching matrices are used to provide phase distribution at output ports that is different for each input port.
The substrates integrated waveguide (SIW) is a promising technology for the antenna feed networks in terms of low radiation and transmission losses with reduced interferences among SIW circuit elements. We propose in this work several beamforming matrices based on SIW technology. This thesis is presented in paper form.
First of all, this work shows the steps taken to finalize the design, fabricate, measurement and evaluation of several Butler matrix topologies. We will see at first that the building components necessary for the proper functioning of such a network: the 3 dB couplers, phase shifters and crossovers. The choice of a configuration will be justified for each of these elements. An electromagnetic simulator (Ansoft HFSS) based on the finite element method (full-wave method) is used in this work. This software package would be able to yield results close to experimental counterparts. Three Butler matrices are developed, the first at 77GHz without crossover, the second is related to a two layer structure at 24 GHz and the third is completely made planar with a cross-over at 12.5 GHz.
The Nolen matrix compared to Butler matrix has the advantages of being free from crossovers in the structure. The loads placed on unused ports in the Blass matrix do not appear in the Nolen matrix which increases efficiency. We propose two architectures, the first one is related to perpendicular configuration in Ku band while the second platform presents a parallel topology which shows a good performance over a broad band around 77 GHz
Guided-wave properties of mode-selective transmission line
The so-called mode-selective transmission line or simply ââMSTLââ is studied theoretically and experimentally. This low-loss and low-dispersion transmission line operates with a frequency-dependent mode-switching behavior. This self-adaptive mode-selective guided-wave structure begins with the propagation of electromagnetic waves over the lower frequency range in the form of a quasi-TEM fundamental mode similar to the microstrip line case, then followed by a fundamental quasi-TE10 mode with reference
to rectangular waveguide over the higher frequency region. To gain insight into the physical mechanism and fundamental features of this mode-selective transmission line, a detailed semi-analytical hybrid-mode analysis is developed through the application of a method of lines. This method allows accurate and effective modeling of MSTL guided-wave properties. Propagation characteristics of this proposed mode-agile structure in terms of dispersion, modal, and loss properties are examined, which leads to the establishment of some basic MSTL design guidelines. Numerical results confirm the expected mode conversion and low-loss behavior through the observation of field evolutions along the structure. For experimental verification, a set of MSTL prototypes are fabricated on two different substrates through dissimilar fabrication processes. Measurements are carried out from dc-to-500 GHz using a vector network analyzer. Excellent agreement
between theoretical and experimental results is observed. It is confirmed that the low-dispersion and lowloss behavior of MSTL makes it an outstanding integrated waveguide in support of high-performance superbroadband signal transmission and/or ultra-fast pulse propagation in a fully-integrated platform
Empty substrate integrated waveguide technology for E plane high-frequency and high-performance circuits
Substrate integrated circuits (SIC) have attracted much attention in the last years because of their great potential of low cost, easy manufacturing, integration in a circuit board, and higher-quality factor than planar circuits. A first suite of SIC where the waves propagate through dielectric have been first developed, based on the well-known substrate integrated waveguide (SIW) and related technological implementations. One step further has been made with a new suite of empty substrate integrated waveguides, where the waves propagate through air, thus reducing the associated losses. This is the case of the empty substrate integrated waveguide (ESIW) or the air-filled substrate integrated waveguide (air-filled SIW). However, all these SIC are H plane structures, so classical H plane solutions in rectangular waveguides have already been mapped to most of these new SIC. In this paper a novel E plane empty substrate integrated waveguide (ESIW-E) is presented. This structure allows to easily map classical E plane solutions in rectangular waveguide to this new substrate integrated solution. It is similar to the ESIW, although more layers are needed to build the structure. A wideband transition (covering the frequency range between 33 GHz and 50 GHz) from microstrip to ESIW-E is designed and manufactured. Measurements are successfully compared with simulation, proving the validity of this new SIC. A broadband high-frequency phase shifter (for operation from 35 GHz to 47 GHz) is successfully implemented in ESIW-E, thus proving the good performance of this new SIC in a practical application.This work was supported by the Ministerio de EconomĂa y Competitividad, Spanish Goverment, under research projects TEC2013-47037-C5-3-R, TEC2013-47037-C5-1-R, AYA2013-49759-EXP, and CSD2010-00064
The access to genetic resources and the sharing of benefits arising from their use face to the patentability of biotechnological inventions. A divisive issue to the test of North/South rapports
La Convention sur la diversitĂ© biologique (CDB, 1992) a Ă©tabli pour la premiĂšre fois en droit international un systĂšme dâaccĂšs aux ressources gĂ©nĂ©tiques (RG) et du partage des avantages qui dĂ©coulent de leur utilisation (systĂšme dâAPA). Ce systĂšme se base sur la reconnaissance de la souverainetĂ© des Ătats sur leurs ressources naturelles, censĂ©e leur permettre dâen contrĂŽler lâutilisation et bĂ©nĂ©ficier des avantages qui en dĂ©coulent. La Convention se prĂ©sentait alors comme un acquis pour les pays du Sud, principaux fournisseurs des RG et par consĂ©quent principaux bĂ©nĂ©ficiaires de ce systĂšme. Deux ans aprĂšs la conclusion de la CDB, lâAccord sur les aspects de la propriĂ©tĂ© intellectuelle qui touchent au commerce (lâAccord) a Ă©tĂ© conclu sous lâĂ©gide de l'OMC. Sous lâinfluence des pays du Nord, cet Accord Ă©tend le champ de la brevetabilitĂ© Ă toutes technologies, y compris celles qui Ă©taient auparavant exclues de ce champ par de nombreux pays, notamment du Sud. Les biotechnologies sont les principales technologies visĂ©es par cette obligation. Ă cet Ă©gard les pays du Sud ont exprimĂ© leur rĂ©ticence en considĂ©rant que lâADPIC nâest pas adaptĂ© aux exigences du systĂšme dâAPA de la CDB puisquâil permet la brevetabilitĂ© des RG qui sont Ă la base des biotechnologies sans prendre en considĂ©ration ces exigences. Ces pays ont en outre estimĂ© que lâAccord risque de compromettre la mise Ćuvre de ce systĂšme. DĂšs lors les deux textes se sont retrouvĂ©s au centre dâun rĂ©el dĂ©bat, entre les pays du Sud et les pays du Nord que ce soit pour condamner leur incompatibilitĂ© ou pour dĂ©fendre leur synergie. Un dĂ©bat qui rĂ©vĂšle un rĂ©el clivage Nord/Sud autour de nombreuses questions.The Convention on Biological Diversity (CBD), concluded in 1992, has established for the first time in international law a genetic resources (GR) regime on access and benefits sharing arising from their use (ABS system). This system is based on the recognition of the sovereignty of States over their natural resources, supposed allow them the control of their use and reaping the associated benefits. Therefore, the Convention was presented as a gain for Southâs countries, the main suppliers of GR and therefore the main beneficiaries of this system. Two years after the conclusion of the CBD, the Agreement on Trade Related aspect of Intellectual Property (TRIPS) was concluded under the aegis of the World Trade Organization (WTO.) Under the influence of Northâs countries concerned to shape the international patent system on their own model, this Agreement extend the patentability scope to all technologies, including those which were excluded from this scope by many countries, especially in South. Biotechnologies are the most concerned by this obligation. In this regard, Southâs countries have expressed reluctance, considering that TRIPS is not adapted to the requirements of the ABS system of CBD since it allows the patentability of GR which are the base of biotechnologies without regard to these requirements. These countries, moreover, considered that the Agreement could compromise the implementation of this system. Therefore, the two texts found themselves at the center of a real debate between the South and the North whether to denounce their incompatibility or support their synergy. A debate that exposes a real North/South division on numerous question
Mise en forme et enrobage des ingrédients pharmaceutiques par procédés supercritiques
Ce travail de thĂšse a Ă©tĂ© dĂ©diĂ© Ă l'Ă©laboration de formulations de mĂ©dicaments par procĂ©dĂ© Supercritique Anti-Solvant (SAS). L'Ă©tude a Ă©tĂ© divisĂ©e en deux sections : la production de co-prĂ©cipitĂ©s de mĂ©dicament / polymĂšre en utilisant le procĂ©dĂ© SAS et lâenrobage de particules de taille micromĂ©trique en utilisant un lit fluidisĂ© couplĂ© au procĂ©dĂ© SAS. L'Ă©thyl cellulose a Ă©tĂ© choisi comme polymĂšre biocompatible pour la prĂ©paration des deux systĂšmes. La micronisation de l'Ă©thyl cellulose par procĂ©dĂ© SAS a Ă©tĂ© rĂ©alisĂ©e avec succĂšs; des particules submicroniques ayant une taille moyenne de 300 nm ont Ă©tĂ© obtenues. Les formulations composites micronisĂ©es, la quercĂ©tine et la rifampicine avec de l'Ă©thyl cellulose ont Ă©tĂ© Ă©laborĂ©es par co-prĂ©cipitation Ă pression et tempĂ©rature modĂ©rĂ©es (10 MPa et 35 °C). L'Ă©tude de faisabilitĂ© d'une nouvelle mĂ©thode dâenrobage par lit fluidisĂ© en milieu supercritique couplĂ© Ă l'utilisation du procĂ©dĂ© SAS a Ă©tĂ© rĂ©alisĂ©e. Ce procĂ©dĂ© vert alternatif permet dâenrober des particules micromĂ©triques avec peu d'agglomĂ©ration et une bonne qualitĂ© du film dâenrobage. Des expĂ©riences dâenrobage de billes de verre ont Ă©tĂ© effectuĂ©es dans des conditions opĂ©ratoires variĂ©es pour deux configurations d'injection diffĂ©rentes, pulvĂ©risation par le haut ou par le bas de lâautoclave. De meilleurs rĂ©sultats ont Ă©tĂ© obtenus dans les expĂ©riences de pulvĂ©risation par le haut, notamment en termes de qualitĂ© de revĂȘtement. Ce travail de thĂšse apporte des Ă©lĂ©ments nouveaux et pertinents pour un meilleur contrĂŽle des procĂ©dĂ©s dâenrobage en milieu supercritique.The elaboration of drug formulations using supercritical anti-solvent process was the subject of this thesis. The study was divided in two sections: production of drug/polymer co-precipitates using SAS process and coating of micron-sized particles using a fluidized bed coupled with SAS process. Ethyl cellulose was chosen as biocompatible polymer for preparing the two systems. The micronization of ethyl cellulose using GRAS ethyl acetate solvent through a supercritical anti-solvent process was successfully performed; submicron particles with mean size of 300 nm were obtained. Micronized drug composites of quercetin or rifampicin with ethyl cellulose at moderate pressure and temperature (10 MPa and 35 °C) were produced by co-precipitation using supercritical anti-solvent process. Depending on the operating conditions, different particle size, particle size distribution and morphology of the product, but also crystallinity and drug loading were observed.The feasibility study of a novel coating method using fluidization in supercritical medium coupled with SAS process has been demonstrated to be a good alternative green process to elaborate micron-sized coated particles with few agglomeration and good coating quality. Coating experiments of glass beads were carried out at different conditions for two different injection configurations, top and bottom spray. Better results were achieved in the top spray experiments in term of coating quality. This Ph. D. work brings new and relevant elements for a better control of the coating processes in supercritical medium
Générateur de rampe de fréquence ultra linéaire pour un systÚme de positionnement local basé sur le principe de radar à onde continue modulée en fréquence
Principe de mesure -- Extraction des objets et estimation de la position -- Principe d'un radar -- Ătude de la frĂ©quence de battement d'un radar FMCW -- La contrainte de la linĂ©aritĂ© -- DĂ©finition du cahier des charges -- Le VCO et les synthĂ©tiseurs -- CaractĂ©risation des propriĂ©tĂ©s du VCO -- Les diffĂ©rentes mĂ©thodes de linĂ©arisation -- Boucle Ă verrouillage de phase -- Structure -- Plage de capture et de verrouillage -- L'application de la PLL Ă la synthĂšse de frĂ©quence -- Ătude de block -- La boucle Ă verrouillage de phase Ă division fractionnelle -- GĂ©nĂ©ration d'une rampe de frĂ©quence -- ContrĂŽle de la PLL et gĂ©nĂ©ration de la rampe -- Circuits PLL ADF4153 fractionnel -- ContrĂŽleur -- Programmation d'une seule frĂ©quence -- LinĂ©arisation d'une Ă©tape -- GĂ©nĂ©ration de la rampe -- Ătude des performances -- Mesure directe de linĂ©aritĂ© -- Banc d'essai -- Mesure de linĂ©aritĂ© -- Mesure en temps rĂ©el -- Estimation de frĂ©quence -- SynthĂšse des erreurs -- Comparaison avec les autres mĂ©thodes -- CoĂ»t
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