Pattern Reconfigurable Cubic Antenna

International audienceA new single-feed reconfigurable antenna for pattern diversity is presented in this paper. The proposed structure is based on a metallic cubic cavity which radiates through rectangular slots. The pattern reconfiguration is achieved with PIN diode switches by short-circuiting slots in their center. The designed antenna can switch between three different radiation patterns which radiate in a 4π steradian range and can receive any incident field polarizations. A prototype of the antenna, including PIN diodes and operating in the 5 GHz band, has been built to demonstrate the feasibility of the concept. Measurements have been conducted and three-dimensional radiation patterns are provided. Diversity performances are evaluated by calculating the envelope correlation coefficient

Mesure de la permittivité du PbZrTiO3 dans les radiofréquences par une méthode en réflexion

National audienceDes couches minces de PbZr0,34Ti0,66O3 ont été réalisées sur substrat de verre par voie chimique et dépôt par centrifugation. Afin de déterminer la permittivité effective de l'échantillon ferroélectrique dans la gamme des hyperfréquences (1-5 GHz), nous utilisons une méthode de mesure en réflexion sur une structure coplanaire. Appuyé sur une succession de transformations conformes, un modèle d'analyse statique de la structure est utilisé permettant de remonter à la permittivité relative du ferroélectrique

Low-cost ku-band dual-polarized and beam switchable cross-type antenna array for satellite communications

International audienceA dual-polarized and beam switchable patch antenna array which works well along the entire Ku-band (10.6-12.7GHz) is introduced in this article. The proposed array is formed with cross-type antenna unit cell and fed by a balanced power division network with microstrip lines. By tuning the length of paths in the feeding network, phase differences taking place among units therefore beam-shifting could be obviously observed on the measured radiation patterns. It is worth while noting that, as patch sharing technique is used in the array arrangement, not only the inter-element distance is significantly decreased but also the beam-shifting angle is distinctly enlarged in the case of same phase-shifting. The proposed antenna can be easily fabricated on very low-cost Teflon substrate with Printing Circuit technology, which might be a good candidate for Direct Broadcast from Satellite (DBS) reception antenna. In this article, the configuration of an experimental 1x4 array and its measured S-parameters and radiation characteristics will be given

New design of an ultra compact printed-circuit antenna

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Contribution à l'étude de dispositifs multifonctions (étude de l'association des fonctions de filtrage et de rayonnement en microélectronique hybride)

Le développement récent des systèmes de télécommunication a pour conséquence une forte augmentation du nombre de services mobiles proposés aux utilisateurs. Il est donc nécessaire de trouver des solutions pour réaliser des systèmes multistandards voire reconfigurables. Dans ce contexte, les architectures de type radio logicielle peuvent être une réponse à ces contraintes car elles permettent de réaliser un grand nombre de traitements des signaux de manière logicielle. Cependant, il n est pas encore possible de converger vers une solution tout numérique. C est pourquoi notre travail a porté sur l optimisation de performances et la miniaturisation des fonctions analogiques. Pour aller dans ce sens, nous avons étudié la possibilité de réaliser des dispositifs multifonctions antenne-filtre en utilisant une technologie planaire hybride. Nous avons donc mené plusieurs études en tenant compte des spécificités de ces technologies planaires dans le cas de structures monocouches et multicouches.The recent development of telecommunication systems has been accompanied with a large increasement in the number of mobile services offered to users. This increase involves the need of developing multistandards systems. Software-radio could give a satisfactory answer to this problem. However, it is not yet possible to make an entire numerical solution. So, this work deals with the optimization and the miniaturization of analogical devices included in the RF front-ent. In this way, we have studied the possibility of designing multifunction structures. In particular, we have focused on the integration of radiating and filtrering functions. In this study, filtering-radiating functions are developped using planar hybrid technologies. It deals not only with classical mono-layer technologies but also with emerging multi-layer technologies.NANTES-BU Sciences (441092104) / SudocNANTES-BU Technologie (441092105) / SudocSudocFranceF

A novel wideband and dual-polarized cross-antenna for satellite communications

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Antenne radioélectrique, procédé de dimensionnement d'un corps plat de l'antenne, et procédé de fabrication d'une telle antenne

Extension internationale brevet France FR20090052458 15/04/200

Contribution à l'étude de la miniaturisation des circuits passifs radiofréquences (application aux circuits d'accès aux antennes)

Le développement des systèmes de communication mobiles et le nombre toujours croissant de services accessibles depuis un même terminal imposent le développement de technologies multistandards reconfigurables toujours plus performantes. Cela implique l optimisation des structures aussi bien en terme de performances que d encombrement. Si les technologies d intégration monolithique ont permis la réalisation compacte des principales fonctions du frontal radio, son volume est maintenant limité par les circuits d interconnexion entre ces fonctions et les circuits d accès aux antennes. Ces travaux ont pour objectif l étude de différentes techniques de miniaturisation de ceux-ci. La modélisation, la caractérisation et les limitations de chacune de ces techniques sont présentées. Elles mènent à la conception de circuits compacts de types coupleurs, déphaseurs ou filtres. Les mesures valident l approche théorique et la faisabilité du gain de place grâce à ces différentes techniques.Recent developments of mobile communications and increasing number of services need the development of multistandard, reconfigurable and reduced size terminals designs. These terminals need reliable, low cost and high-performance technologies. Some techniques, as monolithic integration, have already been studied to optimize size and performances of RF systems. By this way, the terminal size is limited by the interconnecting and antenna access systems, as filtering systems (diplexer) or smart antenna access circuit as Butler matrices. In this work, we propose some techniques of size reduction of theses systems. The study is based on the classical integration technology, which we modified to create compact systems. Modeling, characterisation and limitations of these techniques are presented to design high performance compact systems. Some measurement results are presented to illustrate the size reduction possibility of these techniques.NANTES-BU Sciences (441092104) / SudocNANTES-BU Technologie (441092105) / SudocSudocFranceF

Ku-band dual-polarized patch antenna array arrangement using patch sharing technique

International audiencePatch sharing technique, to the best of the authors' knowledge, is the first time proposed in the application of patch antenna array arrangement. With this approach, the distance between antenna unit cell can be decreased significantly, which the inter-element distance is assumed as a key parameter for beam forming and to control sidelobe level of antenna array. However, most of the time this distance is difficult to decrease due to the profile of antenna unit cell and taking into account of electromagnetic coupling between each unit. In this article, the authors would like to introduce two antenna arrays which are arranged in 1D and 2D separately with the proposed approach, simulated and measured results indicate that patch sharing technique works well

A novel wideband and dual-polarized cross-antenna for satellite communications

International audienc