Antennes co-localisées reconfigurables en fréquence pour systèmes MIMO

National audienceCe papier présente trois antennes co-localisées dont les accès présentent un découplage de l'ordre de 30dB en simulation. La diversité entre chaque antenne est assurée par une combinaison de diversité de polarisation et de rayonnement. Le dispositif a été dimensionné pour fonctionner autour de 5.25GHz avec une largeur de bande d'environ 9.8%. Toutefois, afin de répondre aux besoins actuels concernant la multiplication de fonctions au sein d'un même dispositif, une agilité en fréquence a été introduite via l'utilisation de courts-circuits étendant ainsi la bande à 33%, de 5GHz à 7GHz. La faisabilité pratique d'une telle antenne et la fiabilité des choix des différents paramètres de simulation ont été démontrés précédemment dans le cas d'une antenne cube du même type excitée par un seul monopôle

Collocated Microstrip Antennas for MIMO Systems with a Low Mutual Coupling Using Mode Confinement

WOSInternational audienceIn this paper, collocated antennas for MIMO systems are presented. The structure is composed of a dual-polarized microstrip square patch combined to a dual-polarized microstrip square ring. Consequently, four different radiation patterns are available simultaneously. With a length of about one guided wavelength, the proposed structure is well suited to reduce the MIMO terminal size. The structure operates in the 5.25 GHz band and exhibits a mutual coupling between the four input ports less than -23.5 dB in simulation and -20 dB in measurement. MIMO channel capacity measurements have been performed and demonstrate that the proposed antenna system can replace a classical system based on space diversity

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

Investigation on Cavity/Slot Antennas for Diversity and MIMO systems: the example of a three-port antenna

International audienceThe use, as diversity antennas, of electromagnetic cavities with radiated slots etched on their faces is discussed. From this kind of geometries, many antenna configurations can be designed in order to provide uncorrelated signals. As an example, a three-port antenna which combines polarization and radiation pattern diversities is presented. The structure operates in the 5 GHz band and exhibits a coupling between input ports less than -30 dB in measurement. Envelope correlations between radiation patterns of each port are less than 0.035 which makes this structure well-suited for antenna diversity systems

Ultra-wideband GCPW-MS-GCPW driven electrode for low-cost and wide range application electro-optic modulators

International audienceElectro-optic modulators are key components in high bit-rate optical transmissions. Decreasing the manufacturing cost without damage on performances is one of the most challenging issues for such components. We demonstrate that the electro-optic modulators based on polymer are compatible with high bandwidth requirements. Indeed, according to the results obtained by numerical simulation and partly validated by experiments, with the via-free GCPW-MS-GCPW electrodes proposed and analyzed in this article, the (400 MHz–67 GHz) bandwidth is achievable with electro-optic modulators based on suitable polymers. These encouraging results are very useful for low-cost mass production of polymer-based electro-optic modulators for a wide range of applications: digital and analogue high bit-rate transmissions

Coplanar-Microstrip Transitions for Ultra-Wideband Communications

International audienc

Système multi-antennaires bi-fréquence miniaturisé pour liaison MIMO 4X4

National audienceUn dispositif multi-antennaires pour systèmes MIMO est présenté dans cet article. L'antenne élémentaire utilisée est bi-fréquence afin de couvrir les différentes bandes de la norme WiFi. Les performances du dispositif sont présentées et également évaluées dans un contexte MIMO

Continuously varying coupled transmission lines applied to design band-pass filters

International audienceThis article presents a technique to analyze and optimize Continuously Varying Transmission Lines (CVTL's), used to design microwave band-pass filters in planar technology. For millimeters waves, radiation losses can increase quickly, especially for sharp discontinuities in planar circuits. In this approach, rather than taking account of this effect in a full-wave analysis, we generate structures without discontinuities. Moreover, the line shape is optimized to reduce spurious responses out of the band-pass. For several filters, measurements are compared with simulation results

Généralisation d'une nouvelle méthode de linéarisation d'amplificateurs de puissance avec mémoire

- Cet article présente une généralisation de la méthode de linéarisation des amplificateurs de puissance présentée dans [1]. Cette méthode est basée sur le modèle de Hammerstein de l'amplificateur et permet d'éliminer totalement les produits d'intermodulation et les composantes harmoniques apportées par les distorsions de ce dernier, ainsi que de réduire l'élargissement spectral

A targeted next-generation sequencing assay for the molecular diagnosis of genetic disorders with orodental involvement.

BACKGROUND: Orodental diseases include several clinically and genetically heterogeneous disorders that can present in isolation or as part of a genetic syndrome. Due to the vast number of genes implicated in these disorders, establishing a molecular diagnosis can be challenging. We aimed to develop a targeted next-generation sequencing (NGS) assay to diagnose mutations and potentially identify novel genes mutated in this group of disorders. METHODS: We designed an NGS gene panel that targets 585 known and candidate genes in orodental disease. We screened a cohort of 101 unrelated patients without a molecular diagnosis referred to the Reference Centre for Oro-Dental Manifestations of Rare Diseases, Strasbourg, France, for a variety of orodental disorders including isolated and syndromic amelogenesis imperfecta (AI), isolated and syndromic selective tooth agenesis (STHAG), isolated and syndromic dentinogenesis imperfecta, isolated dentin dysplasia, otodental dysplasia and primary failure of tooth eruption. RESULTS: We discovered 21 novel pathogenic variants and identified the causative mutation in 39 unrelated patients in known genes (overall diagnostic rate: 39%). Among the largest subcohorts of patients with isolated AI (50 unrelated patients) and isolated STHAG (21 unrelated patients), we had a definitive diagnosis in 14 (27%) and 15 cases (71%), respectively. Surprisingly, COL17A1 mutations accounted for the majority of autosomal-dominant AI cases. CONCLUSIONS: We have developed a novel targeted NGS assay for the efficient molecular diagnosis of a wide variety of orodental diseases. Furthermore, our panel will contribute to better understanding the contribution of these genes to orodental disease. TRIAL REGISTRATION NUMBERS: NCT01746121 and NCT02397824.journal articleresearch support, non-u.s. gov't2016 Feb2015 10 26importe