Q-Band Millimeter-Wave Antennas: An Enabling Technology for MultiGigabit Wireless Backhaul

[EN] The bandwidth demands in mobile communication systems are growing exponentially day by day as the number of users has increased drastically over the last five years. This mobile data explosion, together with the fixed service limitations, requires a new approach to support this increase in bandwidth demand. Solutions based on lower-frequency microwave wireless systems may be able to meet the bandwidth demand in a short term. However, with the small-cell mass deployment requiring total capacities of 1 Gb/s/km2, scalable, multigigabit backhaul systems are required. Millimeter-wave technology fits nicely into these new backhaul scenarios as it provides extended bandwidth for high-capacity links and adaptive throughput rate, which allows efficient and flexible deployment. Besides these advantages, millimeter-wave solutions become even more attractive when the cost of backhaul solutions and the cost of spectrum licenses are factored in. Compared to the cost of laying fiber to a cell base station, which is the only other scalable solution, the millimeter-wave solution becomes the most appropriate approach.The research leading to these results received funding from the European Commission's seventh Framework Programme under grant agreement 288267.Vilar Mateo, R.; Czarny, R.; Lee, ML.; Loiseaux, B.; Sypek, M.; Makowski, M.; Martel, C.... (2014). Q-Band Millimeter-Wave Antennas: An Enabling Technology for MultiGigabit Wireless Backhaul. IEEE Microwave Magazine. 15(4):121-130. https://doi.org/10.1109/MMM.2014.2308769S12113015

Matériaux artificiels pour l'optique diffractive

Cette thèse s'intéresse aux optiques diffractives blazées binaires, une famille d'éléments diffractifs composés de structures binaires de dimensions variables mais légèrement inférieures à la longueur d'ondes. Leur principe de fonctionnement est basé sur la synthèse de matériaux artificiel, compsés de traits, de piliers ou d'autres géométries gravèés dans une couche mince diélectrique, dont l'indice effectif dépend du taux de remplissage local de la matière. Ainsi, en variant localement ce taux, il est possible de synthétiser toute fonction de phase. L'objet de cette thèse est d'identifier l'intrêt des matériaux artificiels pour des applications en optique diffractive, domaine en forte croissance avec le progrés des nanotechnologies. Tout d'abord, les résultats expérimentaux dans le visible ont montré que, dans le domaine résonnant, les optiques blazées binaires présentent des performances bien meilleures que les optiques diffractives classiques grâce à un effet de guidage par les structures sub-longueur d'onde constituant les matériaux artificiels...This work concerns blazed binary diffractive optics, a family of diffractive elements composed of binary structures with variable size that is slightly smaller than the wavelength. Their principle of operation is based on artificial materials, composed of ridges, pillars or other simple geometries etched in an dielectric thin film, which effective index depends on the fill factor. Thus, by varying locally the fill factor, one cansynthesize any phase function. The objet of the study is to identify tha advantage of artificial materials for applications in diffractive optic, a domain that is highly increasing with the nano-technology improvements.First, the experimental results obtained in the visible have shown that, in the resonance domain, blazed binary optcs offer higher performances than the standard diffrative optics. It is due to a guiding effect through the sub-wavelength structures that compose the artificial matérials.ORSAY-PARIS 11-BU Sciences (914712101) / SudocSudocFranceF

Blazed-binary elements with periods much larger than the wavelength

International audienceBlazed-binary optical elements with only binary ridges or pillars are diffractive components that mimic standard blazed-echelette diffractive elements. We report on the behavior of one-dimensional blazed-binary optical elements with local periods much larger than the wavelength. For this purpose, an approximate model based on both scalar and electromagnetic theory is proposed. The model is tested against electromagnetic theory computational results obtained for one-dimensional blazed-binary gratings with large periods. An excellent agreement is obtained, showing that the model is able to predict quantitatively the wavelength and the incidence-angle dependences of the diffraction efficiency of blazed-binary structures

Broadband blazing with artificial dielectrics

International audienceThe efficiency of conventional diffractive optical elements with échelette-type profiles drops rapidly as the illumination wavelength departs from the blaze wavelength. We use high dispersion of artificial materials to synthesize diffractive optical elements that are blazed over a broad spectral range ( 1 octave) or for two different wavelengths

Optimisation conjointe d'un masque de phase et d'un algorithme de déconvolution pour l'augmentation de profondeur de champ (Orale)

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Optimisation conjointe d'un masque de phase et d'un algorithme de déconvolution pour l'augmentation de profondeur de champ (Orale)

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