25 research outputs found

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

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    [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

    Towards a metasurface adapted to hyperspectral imaging applications: from subwavelength design to definition of optical properties

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    International audienceWe numerically demonstrate the capability of a single metasurface to simultaneously separate and focus spectral features in accordance with the specifications of a pushbroom hyperspectral imager. This is achieved through the dispersion engineering of a library of two-level TiO2 nano-elements. Sommerfeld integrals are used to confirm our numerical simulations provided by our solver based on Fourier modal method. As a proof of concept, a metasurface with a 175 μm diameter is designed to be compatible with hyperspectral imaging over a spectral range of ±50 nm around 650 nm with a spectral resolution of 8.5 nm and a field of view of 8° around the normal incidence (angular resolution of 0.2°)

    Low-Profile Highly Directive 2D-Beam-Steering Antenna in Ka-band with 3D-printed All-dielectric Sub-wavelength Deflectors

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    International audienceAn elegant combination of a large-aperture planar radiating panel and a 2D-scanning part, implemented through a pair of 3D-printed sub-wavelength deflectors, is presented in this paper to demonstrate a low-profile 2D-scanning antenna system in Ka-band. A 28-cm-diameter prototype was manufactured, with in particular the dielectric deflectors fabricated by 3D printing of a high-permittivity and low-loss composite. The total height of the antenna system is only 4 cm, corresponding to 3.8 wavelengths at 29 GHz. The antenna system demonstrates a steering capacity up to 66° in elevation and 360° in azimuth, with a measured realizedgain of 33 dBi at 0° and 27.4 dBi at 66° scan angle at 29 GHz. The 3dB-bandwidth is 6.5%, covering the 27.75-29.6 GHz range. The measured results validate the simulated steering performance of the system with good agreement and confirm the advantage of using this concept for achieving low-cost, low-profile, lightweight, and simple-configuration 2D-beam-scanning antenna

    Programmable spatial beam shaping of a 100 kHz amplified femtosecond laser

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    International audienceWe present programmable spatial beam-shaping of 100-kHz, 4-µJ amplified femtosecond pulses in a focal plane using wavefront modulation. Phase distributions are determined by a numerical iterative procedure. A non-pixelated optically-addressed liquid crystal light valve is used as a programmable wavefront tayloring device. Top-hat, doughnut, square and triangle shapes with a 20-Μm size are obtained in a focal plane. The suitability for femtosecond laser machining is demonstrated
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