The use of iceberg-keel ploughmarks as proxy indicators of past and present iceberg morphology, keel depth and drift direction has seldom been approached in the southern hemisphere. Using high-resolution multi-beam swath bathymetry of the mid-shelf Pine Island Trough and outermost Weddell Sea shelf regions of Antarctica, detailed analysis of >13,000 iceberg-keel ploughmarks was undertaken. By considering the draft of icebergs calved from Antarctica today, calculated from detailed satellite altimetric datasets by this work, almost all observed ploughmarks were interpreted to be relict features. In Pine Island Trough, ploughmark planform parameters and cross-sections imply calving of a large number of non-tabular icebergs with v-shaped keels from the palaeo-Pine Island-Thwaites ice stream. Geological evidence of ploughmark form and modern water depth distribution indicates calving-margin thicknesses (949 m) and subaerial ice cliff elevations (102 m) equivalent to the theoretical threshold predicted to trigger ice-cliff structural collapse and calving by marine ice-cliff instability (MICI) processes. Thus, ploughmarks provide the first observational evidence of rapid retreat of the palaeo-Pine Island-Thwaites ice stream, driven by MICI processes commencing ~12.3 cal ka BP. On the Weddell Sea shelf, ploughmark morphologies imply considerable variation in palaeo-iceberg shape and size, most likely reflecting calving from multiple source margins. In turn, an absence of grounded ice on the Weddell Sea shelf and a palaeo-oceanographic regime comparable to today are implied at the time of formation. Analysis of a 3D seismic cube of the Sea Lion Field area of the North Falkland Basin reveals iceberg-keel ploughmarks incised into the modern- and palaeo-seafloor, formed by icebergs of varying shape and size that most-likely calved from the Antarctic Ice Sheet during three past glacial periods (estimated ages ~18 - 26.5 ka BP, ~246 ka BP, ~9.8 Ma BP). Despite illustrating the possibility of iceberg drift into the North Falkland Basin today, the relict ploughmark age implies little risk to any seafloor structures in the area, which might be required for hydrocarbon production. By these analyses, the significance of iceberg-keel ploughmarks as indicators of palaeo-glaciology and palaeo-oceanography at the time of formation is emphasised.

Hydroakustiska mätningar har gjorts i nästan två hundra år. Det kan liknas med topografiska mätningar på land och visar hur sjö- eller havsbottnar ser ut. Idag används ekolod vilket är en teknik som skickar ut ljudvågor i vattnet för att mäta hur lång tid det tar för ljudet att studsa på bottnen och sedan komma upp till instrumentet igen. Därefter går det att räkna ut djupet med hjälp av ljudhastighetsberäkningar. Vid inmätning av enkelstråligt ekolod rekommenderas användande av tvärsektioner som kontroll av data. Flerstråligt ekolod behöver däremot inte tvärsektioner då övertäckning mellan stråken används som kontroll. I denna studie undersöks hur antalet tvärsektioner påverkar djupkartor skapade av Seafloor HydroLite TM enkelstråligt ekolod. Detta är även en undersökning av hur djupkartor producerade av SeaFloor HydroLite TM enkelstråligt ekolod skiljer sig mot djupkartor producerade av Kongsberg EM 2040 MK11 flerstråligt ekolod. Studieområdet är 1820 m2 och är beläget vid Forsbackas hamn i Storsjön, Gävle kommun. Vid inmätning av flerstråligt ekolod användes en övertäckning av lägst 50 %. Fem huvudstråk och sju tvärsektioner mättes med enkelstråligt ekolod för området. Djupkartor med olika antal tvärsektioner gjordes i Surfer 10 från enkelstråligt ekolod. Därefter jämfördes djupkartor av enkelstråligt ekolod mot kartor gjorda av data från flerstråligt ekolod för att se hur djupkartorna skiljer sig och för att se hur djupkartorna av enkelstråligt ekolod påverkas av olika antal tvärsektioner. Med användande av flerstråligt ekolod som referens mot djupkartor gjorda av enkelstråligt ekolod blev resultaten att RMS och standardosäkerhet minskar med 1 cm i RMS-värde och med 2 cm i standardosäkerhet. Jämförelse mellan ekolods systemen visar att skillnaden av djupvärderna är runt 10 cm. Slutsatserna från denna studie är att tvärsektioner endast förbättrar kvalitén på djupkartor marginellt vid jämn och enhetlig bottentopografi, men fyller en viktig funktion genom att kontrollera kvalitén av inmätningsdatat. Samt att SeaFloor HydroLite TM klarar av order 1b vid ett djup omkring en till fyra meter om ej kravet på full bottentäckning beaktas. Seafloor HydroLite TM skapar en översiktlig djupkarta medan djupmodellerna från Kongsberg EM 2040 MKII ser mera detaljer. / Hydroacoustic measurements have been conducted for almost two hundred years. It can be compared to topographic measurements on land and shows the appearance of lake or ocean floors. Today, echosounders are used, which is a technique that sends out sound waves into the water to measure the time it takes for the sound to bounce off the bottom and return to the instrument. Sound velocity calculations can then be used to calculate the depth. The use of cross-sections is recommended as a data control of single beam echosounder. However, multi beam echosounders only use overlap as control. This study examines how the number of cross-sections affects depth maps created by Seafloor HydroLite TM single beam echosounder. It also investigates the differences between depth maps produced by the SeaFloor HydroLite TM single beam echosounder and the Kongsberg EM 2040 MK11 multi beam echosounder. The study area covers 1820 m2 and is located at Forsbackas Harbor in Storsjön, Gävle municipality. A minimum overlap of 50% was used for the surveying with the multi beam echosounder. Five main lines and seven cross-sections were measured using the single beam echosounder. Depth maps with different numbers of cross-sections were created using data from the single beam echosounder. The maps from the single beam echosounder were compared to maps created from the data obtained by the multi beam echosounder to assess the differences and the impact of varying numbers of cross-sections on the depth maps from the single beam echosounder. By using the multi beam echosounder as a reference for the depth maps created by the single beam echosounder, the results showed a decrease of 1 cm in RMS value and 2 cm in standard deviation. The comparison between the echosounder systems revealed a difference of around 10 cm in depth values. The conclusions from this study are that cross-sections only marginally improve the quality of depth maps in cases of even and uniform bottom topography but serve an important function in validating the quality of the survey data. Additionally, the SeaFloor HydroLite TM is capable of meeting Order 1b at depths ranging from one to four meters if the requirement for full bottom coverage is not considered. The Seafloor HydroLite TM creates a general overview of the depth map, while the depth models from the Kongsberg EM 2040 MKII provide more detailed information.

Les Systèmes Mobiles de Cartographie basés LIDAR permettent d’obtenir des cartes 3D de l’environnement, qui sont géo-référencées grâce à d’autres capteurs embarqués sur le véhicule : GPS, centrale inertielle, ou encore odomètre sont de tels capteurs qui permettent de localiser le véhicule mobile pendant la campagne d’acquisition. Toutefois, ces cartes manquent de précisions et un affinage des cartes est essentiel dans de nombreux cas d’applications où une précision fine est requise sur les cartes 3D, comme pour des applications de classifications par exemple.Lors de la création de cartes 3D géoréférencées,les données sont tout d’abord acquises par le capteur LIDAR et référencées dans le repère cartésien du laser à l’aide d’un calibrage intrinsèque du capteur d’acquisition. Ensuite, un calibrage extrinsèque du capteur permet de caractériser la transformation entre le capteur et le véhicule, et permet de référencer les données dans le repère « body», lié au véhicule d’acquisition. Enfin, avec la trajectoire du véhicule obtenue en fusionnant les données issues des GPS, centrale inertielle et odomètre, il est possible de géoréférencer les données lasers.Nous proposons dans cette thèse d’affiner les relevés laser issus d’acquisitions effectuées à l’aide d’un véhicule mobile de cartographie, en optimisant plusieurs paramètres différents qui entrent en compte dans le géoréférencement des données. Nous nous sommes intéressés à l’affinement des nuages de points par optimisation des paramètres decalibrage extrinsèque dans un premier temps, puis par optimisation des paramètres de calibrage intrinsèque, et enfin par optimisation des paramètres de translations liés à la trajectoire du véhicule mobile. / LIDAR based Mobile Mapping Systems allowto get 3D maps of the environment, which are globally referenced with the help of others sensors embedded on the vehicle: GPS,Inertial Measurement Unit, or odometer are such sensors which allow localizing the vehicle during the acquisition process. However, these maps lack of precision, and are finement of the maps is necessary for manywork where a good precision is needed on the 3D maps, like classification applications for example.When creating the globally referenced 3D maps, the data are firstly acquired by the LIDAR sensor and referenced in the Cartesian reference frame of the sensor withan intrinsic calibration of the sensor. Then, anextrinsic calibration gives the transformation between the sensor and the vehicle, and gives data referenced in the « body »reference frame, linked to the vehicle. Finally, with the fusion of the data coming from the GPS, the Inertial Measurement Unit and theodometer, the laser data can be globally referenced.In this thesis, we propose to refine the point clouds coming from acquisitions done with a mobile mapping system, by optimizing some parameters which are used in the georeferencing process of the data. Firstly, we were interested in the refinement of point clouds by optimizing the extrinsic calibration parameters, and then we were interested in the refinement of point clouds by optimizing the intrinsic calibration parameters; finally by optimizing the translation parameters of the mobile vehicle trajectory.

Wireless communications have been an indispensable aspect of everyday life, and there is an increasing consumer demand for accessing several wireless communication technologies from a single, compact, mobile device. System-on-package (SOP) technology is an advanced packaging technology that has been proven to realize the convergence of multiple functions into miniaturized, high-performance systems to meet this demand. With the advancements in the SOP technology, the miniaturization of the front-end module has been achieved using embedded passives in multilayer packages. However, the integration of the antenna directly on the module package is still the barrier to achieve a fully-integrated, high-performance RF SOP system. The main reason for this missing link is that integrating the antenna on the package requires miniaturizing the antenna, which is a difficult task. The focus of this dissertation is to design high-performance antennas along with developing techniques for miniaturization and system-on-package (SOP) integration of these antennas to achieve fully-integrated SOP systems using advanced multilayer organic substrates and thin-film magneto-dielectric materials. The targeted spectrum for the antenna designs are 2.4/5 GHz WLAN/WiMAX and 60 GHz WPAN bands. Several novel antenna designs and configurations to integrate the antenna on the package along with the module are discussed in this dissertation. The advanced polymers used in this research are Liquid Crystalline Polymer (LCP), RXP, and thin-film magneto-dielectrics.

Pure Sn and Sn-alloys are widely used in electrical and microelectronic devices as protective layer to prevent oxidation of Cu conductors and also as a component of Pb-free, Sn-based solders. Sn coatings, typically 0.5-10 μm thick, deposited on substrates, e.g., Cu, brass, etc., are prone to spontaneous growth (i.e., without any external stimuli) of Sn whiskers under ambient conditions. The growth of whiskers from Sn plating has caused numerous failures in micro-electronic devices, mainly due to short-circuiting, leading to failure of components or devices. Whisker growth is, thus especially very critical in aviation, space and defines applications, where the electronic components are designed for longer life span. Furthermore, due to miniaturization of electronic devices, the spacing between adjacent conductors or interconnects can be as small as a few hundred nanometres to a few micrometres, making them more prone to whisker induced short-circuiting. Minor alloying of Sn with Pub was the principle way for mitigating the whisker growth in Sn plated components; however, due to the recent worldwide acceptance of European Union’s Restriction of Hazardous Substances (RoHS) act, enforcing Pub-free manufacturing, whisker growth has re-emerged as a reliability issue in Pub-free solders and the Sn plating finishes. Even after decades of research, a universal whisker growth mechanism and hence effective mitigation technique is still not available in the public domain. This is mainly due to the fact that large number of factors that affect the whisker growth directly or indirectly, making it difficult to devise an experimental procedure, which allows studying effect of one factor at a time while keeping other factors constant. Although many mechanistic models for Sn whispering have been proposed in the past, the experimental evidences to support them are lacking. For example, recrystallization of whisker grain was proposed by various researchers; however, a direct observation confirming whisker grain is indeed a recrystallized grain has never been reported. Nevertheless, it is well understood that whisker growth is a form of stress relaxation process and diffusion plays important role in the formation of whiskers. Since Sn is extremely anisotropic with tetragonal crystal structure, the stress state of Sn coatings, as well as the diffusion needed for mass transport of atoms, varies drastically depending upon the direction of interest. Therefore, it is important to study the role of crystallographic texture (both macroscopic and microscopic) on whisker propensity by systematically varying the crystallographic texture of Sn coating while keeping thickness, grain size, substrate material, and post-deposition storage conditions the same. Better understanding of role of macro- and micro- texture is very crucial before any whispering mechanism can be proposed. Furthermore, recent studies indicate that role of stresses in Sn coatings driving whisker growth is not fully understood. It is generally accepted that compressive stress in Sn coating is the main factor that drives the whisker growth. However, whiskers were also observed when Sn coating was under tensile stress, making the role of stress controversial. Again, the stresses in Sn have multiple origins and need a systematic approach to understand their origin, quantify them and then relate it to whisker growth. Such systematic approach was never adopted in previous works. Hence, the current thesis aims to address the role of macro- and micro- crystallographic texture, stress regeneration mechanism, nature (i.e., magnitude and sign) of stress and stress gradient in the Sn coatings via systematic variation of texture, post-deposition storage conditions and substrate composition, including deposition of an interlayer in between Sn coating and the brass or Cu substrate. Whisker growth was studied from electro-deposited Sn coatings. The deposition parameters were optimized for producing different thickness and grain orientations. X-Ray diffraction (XRD) techniques were used to extract macro-texture of the coatings. The macro-texture measurement using XRD and micro-texture measurement using electron backscatter diffraction (EBSD) showed the same dominant and the second dominant orientations. It was observed that current density and deposition temperature, which are the two main electro-deposition parameters, significantly influence the crystallographic orientation of the grains. Thus, the global or macro-texture can be manipulated by changing the deposition parameters systematically. It was observed that whisker propensity increases drastically by growth of low index planes, such as (100) and (110), during deposition. Hence, proper selection of deposition parameters that lead to growth of high index planes can be used to suppress the whisker growth. Furthermore, micro-texture surrounding whisker grain was studied using EBSD technique by observing the same set of grains surrounding a whisker grain before and after whispering. Orientation imaging microscopy (OIM) maps of several whisker regions clearly indicate that whiskers preferentially grow from low index planes, such as (100), etc. Furthermore, using orientation dependent stiffness mapping (in-plane and out-of-plane), it was noticed that whiskers preferentially grew from regions of soft oriented grains (low modulus) surrounded by hard orientations. In addition, grain boundary disorientation analysis revealed presence of high fraction of high angle grain boundaries (HAGBs) in the vicinity of whisker grain. It was observed that overall fraction of HAGBs in the whispering region was 0.7 while the fraction of HAGBs surrounding and leading to whisker grain was 0.85. In addition, it was observed that whisker grew from pre-existing grain and not from the recrystallized grain. Also, grain boundary sliding was not observed as a pre-requisite for whisker growth in Sn coatings on brass substrate. The local stress field around the whisker grain also plays a crucial role in whisker growth. Therefore, local stress field around whisker site was simulated using crystal plasticity simulation by incorporating grid resolved spatial description of orientation in terms of Euler’s angles. The crystal plasticity model included slip systems of Sn and other material parameters, such as anisotropic elastic stiffness constants, critical resolved shear stresses for different slip systems, etc. Thus, the slip in individual grain was accounted following homogenization to maintain compatibility at grain boundaries. The simulated stress field shows that both in-plane and out-of-plane stresses were highly inhomogeneous without any unique condition around whisker grain. It has been observed that high compressive hydrostatic stresses develop in the vicinity of the whisker grain, while whisker grain is slightly tensile. Therefore, the gradient of hydrostatic stress around the whisker suggests whisker growth is mainly controlled by vacancy transport phenomenon. The stress in Sn coatings may originate from many factors, such as residual stress inherent to electro-deposition, diffusion of substrate atoms (Cu, Zn, etc.) into the coating, formation of interfacial intermetallic compound (IMC) layer, segregation of impurities at Sn grain boundaries, formation of surface oxide layer, and coefficient of thermal expansion (CTE) mismatch between in Sn and substrate as well as between differently orientated grains of Sn. Therefore, it is important to understand the dominant stress regeneration mechanism responsible for whisker growth. To identify dominant mechanism, which can continuously regenerate the compressive stress in Sn, samples deposited under fixed electro-deposition conditions were exposed to different post-deposition storage conditions, such as isothermal aging at room temperature, 50 °C, 150 °C, and thermal cycling from -25 to 85 °C with and without hold time at the highest temperature. It has been observed that Cu6Sn5 IMC growth due to the inter-diffusion of Cu and Sn atoms is the dominant mechanism responsible for whisker growth. Both growth kinetics and morphology of IMC have a significant impact on whisker growth. The role of CTE mismatch in regenerating compressive stresses in Sn coatings on brass substrate for whisker growth is highly limited. The substrate composition as well as the under layer metallization affects the inter-diffusion between Sn and the substrate atoms and therefore IMC growth, which is mainly responsible for whisker growth in Sn coatings on brass or Cu substrates. The effects of substrate composition on whisker growth was studied by using pure Cu, brass (65 wt. % Cu 35 wt. % Zn) and Ni (bulk and electro-deposited under layer) as substrate. Whisker growth was more rapid if brass substrate was used instead of pure Cu. Whiskers were not observed when Sn was deposited on either bulk Ni or when Ni under layer was electro-deposited on brass or Cu substrates prior to Sn deposition. Ni under layer effectively stops the diffusion of Cu into Sn, thus avoiding the growth of Cu6Sn5 (which places Sn coatings under compressive stress). Thus, it is clear that continuous formation of Cu6Sn5 at the interface provides the long-term driving force for whisker growth. Since the whisker growth is a stress driven phenomenon, it is important to understand the stress evolution in Sn coatings. Stress state of the Sn coatings was studied using custom-built laser curvature set-up with multi-beam optical stress sensor (MOSS). This allowed monitoring of curvature change of the coating-substrate system in real time and the bulk average stress was calculated using Stoney’s equation. For multi-layer system such as Sn deposited on pre-deposited Ni under layer on brass substrate modified Stoney’s equation was used. In case of Sn deposited on brass without any under layer, it is known that the Cu6Sn5 IMC do not form a continuous layer at the interface between Sn and substrate under aging at ambient conditions, therefore, the curvature change due to IMC can be neglected. In addition, glancing angle X-ray diffraction was employed to analyse stress in the top surface region of the coating. The variation of glancing angle allowed probing strain at different penetration depths. Both the bulk stress and the stress in only near surface region evolve with time. The residual bulk stresses in Sn coatings are tensile immediately after deposition. The residual stresses relax very quickly upon room temperature aging and become compressive. The bulk of Sn coatings on brass substrate progressively become more compressive upon continued aging. However, stresses in Sn coatings deposited on brass substrate with Ni under layer saturate quickly at low compressive stress. Surprisingly, stress in the top-most region of Sn coating measured using XRD evolve differently. The surface of Sn coating deposited on brass substrate is compressive initially and progressively become more tensile (less compressive), while the initial compressive stress in the sample with Ni under layer saturated at a higher compressive stress than the bulk stress value recorded from curvature measurement. Therefore, the surface of the Sn coatings with Ni under layer is always more compressive than the bulk stress in the Sn coating. Therefore, a negative stress gradient for the diffusion of Sn atoms towards surface is never established and whiskers do not grow in these Sn coatings. Interestingly, through thickness voids are observed in the Sn coatings on Ni. Contrarily, in Sn coatings without Ni under layer after 170 h of aging, the surface stress becomes more tensile than the bulk of the Sn coating, favouring continuous migration of atoms from the highly compressed region near Cu6Sn5 IMC layer to the stress-free whisker root. Aforementioned observation indicates the crucial role of negative stress gradient in the mass transport of atoms required for whispering. The importance of stress and stress gradient was further studied by analysing the effect of externally imposing stress and stress gradient on whisker growth. The stresses were applied using a three-point bend setup. It has been observed that externally applied stress accelerates the whisker growth. This is mainly because applied stress alters the diffusion kinetics and growth of Cu6Sn5 IMC at the interface. However, the coating under tensile stress shows more whisker growth as compared to the coating under high compressive stress. This is attributed to the fact the coating under tensile stress is under higher negative stress gradient. Therefore, it is proposed that out-of-plane stress gradient is more important rather than the sign and the magnitude of stress in determining the propensity of whisker growth in Sn coatings.

No description available.

<p dir="ltr">Several industrial and commercial bulk material management applications rely on accurate, current stockpile volume estimation. Proximal imaging and LiDAR sensing modalities can be used to derive stockpile volume estimates in outdoor and indoor storage facilities. Among available imaging and LiDAR sensing modalities, the latter is more advantageous for indoor storage facilities due to its ability to capture scans under poor lighting conditions. Evaluating volumes from such sensing modalities requires the pose (i.e., position and orientation) parameters of the used sensors relative to a common reference frame. For outdoor facilities, a Global Navigation Satellite System (GNSS) combined with an Inertial Navigation System (INS) can be used to derive the sensors’ pose relative to a global reference frame. For indoor facilities, GNSS signal outages will not allow for such capability. Prior research has developed strategies for establishing the sensor position and orientation for stockpile volume estimation while relying on multi-beam spinning LiDAR units. These approaches are feasible due to the large range and Field of View (FOV) of such systems that can capture the internal surfaces of barn and dome storage facilities.</p><p dir="ltr">The mechanical movement of multi-beam spinning LiDAR units together with the harsh conditions within indoor facilities (e.g., excessive humidity, dust, and corrosive environment in deicing salt storage facilities) limit the use of such systems. With the increasing availability of solid-state LiDAR units, there is an interest in exploring their potential for stockpile volume estimation. In spite of their higher robustness to harsh conditions, solid-state LiDAR units have shorter distance measurement range and limited FOV when compared with multi-beam spinning LiDAR. This research presents a strategy for the extrinsic calibration (i.e., estimating the relative pose parameters) of installed solid-state LiDAR units inside stockpile storage facilities. The extrinsic calibration is made possible using deployed spherical targets and a complete, reference scan of the facility from another LiDAR sensing modality. The proposed research introduces strategies for: 1) automated extraction of the spherical targets; 2) automated matching of these targets in the solid-state LiDAR and reference scans using invariant relationships among them; and 3) coarse-to-fine estimation of the calibration parameters. Experimental results in several facilities have shown the feasibility of using the proposed methodology to conduct the extrinsic calibration and volume evaluation with an error percentage less than 3.5% even with occlusion percentages reaching up to 50%.</p>

Les systèmes de communications sans fils actuels imposent des contraintes très sévères en termes de la capacité du canal, la qualité de transmission tout en gardant les niveaux d'interférences et multi-trajets assez faibles. De telles contraintes ont rendu les antennes multifaisceaux un élément essentiel dans ces systèmes. Parmi les techniques permettant de réaliser une antenne multifaisceaux (sans avoir recours aux systèmes à balayages électroniques), un réseau d'antennes élémentaires est associé à un réseau d'alimentation (une matrice) à formation de faisceau (Beam Forming Network-BFN). Parmi les différents types de ces matrices, la matrice de Butler a reçu une attention particulière. Ceci est dû au fait qu'elle est théoriquement sans pertes et qu'elle emploie un nombre minimum de composants (coupleurs et déphaseurs) afin de générer l'ensemble de faisceaux orthogonaux demandé (avec l'hypothèse que le nombre de faisceau est une puissance de 2). Néanmoins, la matrice de Butler a un problème de conception majeur. Ce problème réside dans la structure de la matrice qui renferme des croisements ce qui a été adressé par différents travaux de recherches dans la littérature. Les Guide Intégré au Substrat (GIS) offrent des caractéristiques intéressants pour la conception des composants microondes et millimétriques faciles à intégrer sur un même support avec d'autres composants planaires. Les composants à base de GIS combinent les avantages des guides d'ondes rectangulaires, comme leur grand facteur de qualité Q, leur faibles pertes tout en étant compatible avec les technologies à faibles coûts comme le PCB et le LTCC. Vus ses caractéristiques attrayants, la technologie GIS devient un bon candidat pour la réalisation des matrices multifaisceaux faciles à intégrer avec d'autres systèmes en technologies planaires ou à base de guide GIS. Dans cette thèse, de nouveaux composants passifs sont développés en exploitant la technologie GIS en multicouches en vue de la réalisation d'une matrice de Butler 4x4 compacte et large bande. Les composants recherchés sont donc des coupleurs et des déphaseurs ayant des performances large bande en termes des amplitudes des coefficients de transmissions et les phases associés tout en gardant de faibles niveaux de pertes et de bonnes isolations. Différents techniques pour l'implémentation de déphaseurs large bande en technologie GIS sont présentés. Une nouvelle structure à base d'une propagation composite : main gauche main droite (Composite Right/Left- Handed, CRLH) dans un guide d'onde est proposée. La structure consiste d'un guide d'onde monocouche ayant des fenêtres inductives et des fentes transversales à réactances capacitives pour synthétiser l'inductance parallèle et la capacité série main gauche, respectivement. La structure est adaptée pour les réalisations de déphaseurs compacts en technologie GIS. Bien que les pertes d'insertions restent dans le même ordre de grandeur de celles des structures CRLH à base d'éléments non-localisés, ces niveaux de pertes restent relativement grands par rapport aux applications nécessitant plusieurs déphaseurs. Les déphaseurs à bases de GIS ayant des longueurs égales et des largeurs variables sont ensuite abordés. Ce type de déphaseur est effectivement très adapté à la technologie GIS qui permet des réalisations de parcours avec différentes formes (parcours droits, courbés, coudés, ..) tout en assurant des différences de phase large bande. Afin de satisfaire de faibles pertes d'insertions pour une large dynamique de phase, la longueur de ces déphaseurs est en compromis avec les variations progressives des différentes largeurs associées aux valeurs de déphasages requises. Une transition large bande, double couche et à faible perte est ainsi proposée. La transition est analysée à partir de son circuit électrique équivalent afin d'étudier les performances en termes de l'amplitude et la phase du coefficient de transmission par rapport aux différents paramètres structurels de la transition. Cette transition est ensuite exploitée pour développer un déphaseur à trois couches, large bande, en GIS. La structure consiste effectivement d'un guide d'onde replié à plusieurs reprises sur luimême selon la longueur dans une topologie trois couches à faibles pertes. De nouveaux coupleurs double couche en GIS sont également proposés. Pour les applications BFNs, une structure originale d'un coupleur large bande est développée. La structure consiste de deux guides d'onde parallèles qui partagent leur grand mur ayant une paire de fentes inclinées et décalées par rapport au centre de la structure. Une étude paramétrique détaillée est faite pour étudier l'impact des différents paramètres des fentes sur l'amplitude et la phase du coefficient de transmission. Le coupleur proposé a l'avantage d'assurer une large dynamique de couplage ayant des performances larges bandes en termes des amplitudes et les phases des coefficients de transmission avec de faibles pertes et de bonnes isolations entre le port d'entré et celui isolé. D'autre part, contrairement à d'autres travaux antérieurs et récents qui souffraient d'une corrélation directe entre la phase en transmission et le niveau de couplage, la structure proposée permet de contrôler le niveau de couplage en maintenant presque les mêmes valeurs de phase en transmission pour différents niveaux de couplage. Ceci le rend un bon candidat pour les BFNs déployant différents coupleurs telle la matrice de Nolen. Une deuxième structure originale d’un coupleur bibande est également proposée. La structure consiste de deux coupleurs concentriques en guide nervuré intégré au substrat avec un motif innovant de démultiplexage à base de GIS. Ce coupleur a été développé conjointement avec M. Tarek Djerafi de l’Ecole Polytechnique de Montréal dans un cadre de collaboration avec le Prof. Ke Wu. Finalement, pour l'implémentation de la matrice de Butler, la topologie double couche est explorée à deux niveaux. Le premier consiste à optimiser les caractéristiques électriques de la matrice, tandis que le second concerne l'optimisation de la surface occupée afin de rendre la matrice la plus compacte possible sans dégrader ses performances électriques. D'une part, la structure double couche présente une solution intrinsèque au problème de croisement permettant ainsi une plus grande flexibilité pour la compensation de phase sur une large bande de fréquence. Ceci est réalisé par une conception adéquate de la surface géométrique sur chaque couche de substrat et optimiser les différentes sections de GIS avec les différents parcours adoptés. La deuxième étape consiste effectivement à optimiser la surface sur chaque couche en profitant de la technologie GIS. Ceci consiste à réaliser des murs latéraux communs entre différents chemin électrique de la matrice en vue d'une compacité optimale. Les deux prototypes de matrices de Butler 4x4 sont optimisés, fabriqués et mesurés. Les résultats de mesures sont en bon accord avec ceux de la simulation. Des niveaux d'isolations mieux que - 15 dB avec des niveaux de réflexions inférieurs à -12 dB sont validés expérimentalement sur plus de 24% de bande autour de 12.5 GHz. Les coefficients de transmission montrent de faibles dispersions d'environ 1 dB avec une moyenne de -6.8 dB, et 10° par rapport aux valeurs théoriques, respectivement, sur toute la bande de fréquence. / Multibeam antennas have become a key element in nowadays wireless communication systems where increased channel capacity, improved transmission quality with minimum interference and multipath phenomena are severe design constraints. These antennas are classified in two main categories namely adaptive smart antennas and switched-beam antennas. Switched-beam antennas consist of an elementary antenna array connected to a Multiple Beam Forming Network (M-BFN). Among the different M-BFNs, the Butler matrix has received particular attention as it is theoretically lossless and employs the minimum number of components to generate a given set of orthogonal beams (provided that the number of beams is a power of 2). However, the Butler matrix has a main design problem which is the presence of path crossings that has been previously addressed in different research works. Substrate Integrated Waveguide (SIW) features interesting characteristics for the design of microwave and millimetre-wave integrated circuits. SIW based components combine the advantages of the rectangular waveguide, such as the high Q factor (low insertion loss) and high power capability while being compatible with low-cost PCB and LTCC technologies. Owing to its attractive features, the use of SIW technology appears as a good candidate for the implementation of BFNs. The resulting structure is therefore suitable for both waveguide-like and planar structures. In this thesis, different novel passive components (couplers and phase shifters) have been developed exploring the multi-layer SIW technology towards the implementation of a two-layer compact 4×4 Butler matrix offering wideband performances for both transmission magnitudes and phases with good isolation and input reflection characteristics. Different techniques for the implementation of wideband fixed phase shifters in SIW technology are presented. First, a novel waveguide-based CRLH structure is proposed. The structure is based on a single-layer waveguide with shunt inductive windows (irises) and series transverse capacitive slots, suitable for SIW implementations for compact phase shifters. The structure suffers relatively large insertion loss which remains however within the typical range of non-lumped elements based CRLH implementations. Second, the well-known equal length, unequal width SIW phase shifters is discussed. These phase shifters are very adapted for SIW implementations as they fully exploit the flexibility of the SIW technology in different path shapes while offering wideband phase characteristics. To satisfy good return loss characteristics with this type of phase shifters, the length has to be compromised with respect to the progressive width variations associated with the required phase shift values. A twolayer, wideband low-loss SIW transition is then proposed. The transition is analyzed using its equivalent circuit model bringing a deeper understanding of its transmission characteristics for both amplitude and phase providing therefore the basic guidelines for electromagnetic optimization. Based on its equivalent circuit model, the transition can be optimized within the well equal-length SIW phase shifters in order to compensate its additional phase shift within the frequency band of interest. This twolayer wideband phase shifter scheme has been adopted in the final developed matrix architecture.This transition is then exploited to develop a three-layer, multiply-folded waveguide structure as a good candidate for compensated-length, variable width, low-loss, compact wideband phase shifters in SIW technology. Novel two-layer SIW couplers are also addressed. For BFNs applications, an original structure for a two-layer 90° broadband coupler is developed. The proposed coupler consists of two parallel waveguides coupled together by means of two parallel inclined-offset resonant slots in their common broad wall. A complete parametric study of the coupler is carried out including the effect of the slot length, inclination angle and offset on both the coupling level and the transmission phase. The first advantage of the proposed coupler is providing a wide coupling dynamic range by varying the slot parameters allowing the design of wideband SIW Butler matrix in two-layer topology. In addition, previously published SIW couplers suffer from direct correlation between the transmission phase and the coupling level, while the coupler, hereby proposed, allows controlling the transmission phase without significantly affecting the coupling level, making it a good candidate for BFNs employing different couplers, such as, the Nolen matrix. A novel dual-band hybrid ring coupler is also developed in multi-layer Ridged SIW (RSIW) technology. This coupler has been jointly developed with Tarek Djerafi in a collaboration scenario with Prof. Ke Wu from the Ecole Polytechnique de Montréal. The coupler has an original structure based on two concentric rings in RSIW topology with the outer ring periodically loaded with radial, stub-loaded transverse slots. A design procedure is presented based on the Transverse Resonance Method (TRM) of the ridged waveguide together with the simple design rules of the hybrid ring coupler. A C/K dual band coupler with bandwidths of 8.5% and 14.6% centered at 7.2 GHz and 20.5 GHz, respectively, is presented. The coupler provides independent dual band operation with low-dispersive wideband operation. Finally, for the Butler matrix design, the two-layer SIW implementation is explored through a two-fold enhancement approach for both the matrix electrical and physical characteristics. On the one hand, the two-layer topology allows an inherent solution for the crossing problem allowing therefore more flexibility for phase compensation over a wide frequency band. This is achieved by proper geometrical optimization of the surface on each layer and exploiting the SIW technology in the realization of variable width waveguides sections with the corresponding SIW bends. On the other hand, the two-layer SIW technology is exploited for an optimized space saving design by implementing common SIW lateral walls for the matrix adjacent components seeking maximum size reduction. The two corresponding 4×4 Butler matrix prototypes are optimized, fabricated and measured. Measured results are in good agreement with the simulated ones. Isolation characteristics better than -15 dB with input reflection levels lower than -12 dB are experimentally validated over 24% frequency bandwidth centered at 12.5 GHz. Measured transmission magnitudes and phases exhibit good dispersive characteristics of 1dB, around an average value of -6.8 dB, and 10° with respect to the theoretical phase values, respectively, over the entire frequency band.

Les travaux de cette thèse portent sur la conception d'antennes multi-faisceaux. Ces dernières permettent à plusieurs faisceaux de partager la même partie rayonnante et offrent la possibilité d'avoir simultanément un fort gain et une grande couverture angulaire. Pour leur fonctionnement, ces antennes se basent sur des réseaux à formation de faisceaux, qui peuvent être groupés en deux catégories : les réseaux formateurs de faisceaux de type quasi-optique et les réseaux formateurs de faisceaux de type circuit. Plusieurs structures antennaires reposant sur ces types de réseaux à formation de faisceaux sont proposés dans cette thèse : structures pillbox simples intégrant les deux variantes de la technique mono-pulse pour augmenter la résolution angulaire de l'antenne, lentilles de Rotman bicouche et multicouche, pour le cas quasi-optique ; réseaux phasés pour applications SATCOM (projet ANR) et matrice de Butler avec circuit de contrôle des niveaux de lobes secondaires pour le cas circuit. Les différents concepts ont été étudiés dans différentes bandes de fréquences : Ku, K et V. Pour des raisons de coût essentiellement, deux technologies ont été retenues : La technologie SIW (Substrate Integrated Waveguide), qui associe les avantages de la technologie des circuits imprimés et celles de la technologie guide d'ondes. Des efforts particuliers ont été faits pour l'implémentation de structures multicouches car nous arrivons à ce stade à la limite du savoir faire industriel national dans ce domaine. La technique de « Diffusion Bounding » développée au « Ando and Hirokawa lab » du TIT (Tokyo Institute of Technology) et qui consiste à assembler de fines couches métalliques sous haute température et haute pression. Cette technique permet le développement d'antennes en guides creux avec des efficacités supérieures à 80% en bande millimétrique. / This PhD thesis deals with the design of multi-beam antennas. A single radiating aperture is used to generate several beams with high gain and a large field of view. The multi beam operation is achieved by using two topologies of Beam Forming Networks (BFN): quasi optical BFN, and circuit-based BFN. For each category, several solutions have been proposed and validated experimentally. In particular, for the quasi-optical configurations, pillbox structures, mono-pulse antennas in pillbox technology, and multi-layer Rotman lenses have been considered. On the other hand, for circuit-based multi-beam antennas, two solutions have been analyzed: a phased array for SATCOM applications in the framework of a national ANR project and a Butler matrix with controlled side-lobe levels for the radiated beams within a collaboration with the Tokyo Institute of Technology, Japan. The proposed concepts and antenna solutions have been considered in different frequency bands: Ku, K and V. Two technologies have been mainly adopted for the fabrication of the various prototypes: Substrate Integrated Waveguide technology (SIW) which combines the advantages in terms of cost of the printed circuit board (PCB) fabrication process with the efficiency of classical waveguide technology. Considerable efforts have been devoted to the implementation of multilayer SIW structures to overcome and go beyond the current state of the art at national level on PCB fabrication process. Diffusion Bounding Technique, developed at “Ando and Hirokawa lab” at the Tokyo Institute of Technology, which consists of bonding laminated thin metal plates under high temperature and high pressure. This technique allows the fabrication of planar hollow waveguide structures with efficiencies up to 80% in the millimeter wave-band.