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

Etude et réalisation d'une source<br />térahertz accordable de grande pureté<br />spectrale

Continuous high-purity THz generation through photomixing is a very promising technique for future THz local oscillators. Consequently, we have proposed an innovative photomixing architecture based on a dual frequency laser emitting around 1 µm associated with a matched band gap photoconductor. Working with this wavelength allows the use of compact and low cost diode pumped solid state laser and also the use of photoconductive materials with the required electrical properties for a CW generation over a large frequency bandwidth.Therefore, we have developed 2 dual-frequency lasers using Yb doped active mediums (KGW and CaF2) emitting around 1 µm. They permit the generation of narrow line-width (We then have studied and characterised 2 photoconductive materials compatible with an illumination around 1 µm: InGaAsN and LTG-In.23Ga.77As grown on metamorphic layer and Beryllium doped. Optical and electrical properties of those two materials have been tested and compared to the LTG-GaAs properties.After a theoretical study of photomixers (including the hole participation), we have performed CW THz generation experiments using the LTG-InGaAs devices coupled to the dual-frequency laser: we have detected signals of few tens of nW, tunable up to 2 THz.Finally, we have proposed a new travelling wave vertical photomixer architecture. Modelisation have shown that the expected generated power (0,2 mW at 1 THz), the tunability (0-3 THz) and spectral purity (Ainsi, nous avons développé 2 lasers bi-fréquence amplifiés utilisant des milieux actifs (KGW et CaF2) dopés Yb dont l'utilisation permet de générer des puissances optiques supérieurs à 1 W ainsi qu'un signal de battement électrique continu de bonne pureté spectrale (Nous avons ensuite étudié et caractérisé 2 matériaux photoconducteurs compatibles avec une illumination à 1 µm : l'InGaAsN et l'In.23Ga.77As-BT épitaxié à basse température (BT) sur substrat métamorphique et dopé Be. Les propriétés de ces deux matériaux ont été étudiées et comparées avec celles du GaAs-BT.Après avoir modélisé le fonctionnement de photomélangeurs (en prenant en compte la participation des trous) nous avons effectué des expériences de photomélange : nous avons détecté un signal de quelques dizaines de nW dont la fréquence a pu être accordée jusqu'à 2 THz.Enfin, nous avons proposé un nouveau type de photomélangeur guide vertical. Les modélisations ont montré que la puissance THz émise (0,2 mW à 1 THz), l'accordabilité (0-3 THz) et la pureté spectrale du signal généré (< 30 KHz) de cette source devraient en faire une des plus attractive dans cette gamme de fréquence

Étude et réalisation d'une source térahertz accordable de grande pureté spectrale

LILLE1-BU (590092102) / SudocSudocFranceF

Multi Sensor Millimeter-Wave System for Hidden Objects Detection by Non-Collaborative Screening

International audienc

Single-Prism Risley Scanner at Ka-Band

International audienceThis contribution presents a new Risley scanner architecture for beam-steering antennas. Classical Risley scanners are based on a feed (source) illuminating a system of two prisms. The source usually radiates a directive beam aligned with the central axis of the scanner. The azimuthal positions of the two prisms around their axis controls the pointing direction of the whole system, both in azimuth and elevation. Here, we propose first to reduce the complexity and profile of the system by substituting the source and the first prism of the scanner with a leaky-wave feed. The leaky-wave feed radiates its main beam at about 30 degrees relatively to its normal, and is based on a sinusoidally modulated metasurface fed by a pillbox beamformer. Second, we propose to manufacture the second prism using dielectric loaded metallic waveguides, realized through the combination of two additively manufactured parts. The proposed structure is validated by full-wave simulations and the fabrication and testing of a prototype. The antenna operates in the 19.2-21.2 GHz band for a field of view of 360 degrees in azimuth and 60 degrees in elevation