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11 results on '"Francois Doucet"'

1. A Circularly Polarized Parallel Plate Waveguide Lens-Like Multiple-Beam Linear Array Antenna for Satcom Applications

Author

Nicola Bartolomei, Darwin Blanco, Francois Doucet, Etienne Girard, Herve Legay, Nelson J. G. Fonseca, Ronan Sauleau, and Mauro Ettorre

Subjects
Beamformers, circular polarization, parallel plate waveguides, satcom applications, septum polarizer, Electrical engineering. Electronics. Nuclear engineering, TK1-9971
Abstract

This work presents a full metal circularly-polarized lens-like antenna for Satcom applications at Ka-band. The antenna is composed of two continuous parallel plate waveguide (PPW) quasi-optical beamformers (QOBF), feeding an array of septum polarizers to generate circular polarization. The QOBFs operate over a wide band and provide a multi-beam coverage over a large field of view in the azimuthal plane, while maintaining a relatively simple mechanical design. The array of septum polarizers is based on a stepped profile to generate circular polarization with a good polarization purity in the uplink of Ka-band (27 - 31 GHz). The antenna is fully realized in aluminium. The antenna system provides 14 beams with alternating right/left handed circular polarization (RHCP/LHCP) with an axial ratio (AR) below 3 Db over an angular range of ±19° in the uplink of Ka-Band. The maximum gain in the azimuthal plane at 30 GHz is about 21 dB over the whole angular range, with a scan loss lower than 1.5 dB. The antenna efficiency is better than 78% for all beams in the operative band.

Published
2023
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2. Compact Planar Beamformer Using Multiple Continuous Parallel-Plate Waveguide Delay Lenses

Author

Francois Doucet, Nelson J. G. Fonseca, Etienne Girard, Xavier Morvan, Ronan Sauleau, Institut d'Électronique et des Technologies du numéRique (IETR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Nantes Université - pôle Sciences et technologie, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ), Dassault Aviation, European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Thales Alenia Space [Toulouse] (TAS), THALES [France], European Space Agency (ESA), Thales Alenia Space, France, and ESA's Networking/Partnering Initiative (NPI) [4000117405/16/NL/MH]

Subjects
parallel-plate waveguide (PPW) beamformer, [SPI]Engineering Sciences [physics], Geometrical optics (GO), line source, Electrical and Electronic Engineering, multiple beam antenna
Abstract

International audience; A compact planar beamformer using multiple shaped continuous parallel-plate waveguide delay lenses is proposed in this letter. The original design, based on a single-shaped continuous delay lens, had demonstrated excellent scanning properties over the portion of the K-a-band allocated to uplink satcom (27.5-31 GHz). However, its height, due to the transversal ridge and cavity, was limiting its use in more advanced antenna systems. A design methodology is proposed here to achieve similar focusing properties while reducing significantly the beamformer's height. A specific design is demonstrated with a height reduced by a factor of three when compared to the original design. A reduction of the longitudinal dimension is also proposed by introducing two additional straight ridges and cavities. A prototype was manufactured and tested successfully, with RF performance similar to those of the reference design besides slightly higher insertion losses. This compact design enables to stack multiple lenses to produce two dimensional (2-D) beamforming.

Published
2022

3. Shaped Continuous Parallel Plate Delay Lens With Enhanced Scanning Performance

Author

Etienne Girard, Laurent Le Coq, Francois Doucet, Ronan Sauleau, Xavier Morvan, Herve Legay, Nelson J. G. Fonseca, Institut d'Électronique et des Technologies du numéRique (IETR), Université de Nantes (UN)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), European Space Agency (ESA), Thales Alenia Space (TAS), THALES, Thales Alenia Space, France of ESA, European Union through the European Regional Development Fund (ERDF) European Union (EU), Ministry of Higher Education and Research, Brittany through the CPER Project SOPHIE/STIC Ondes, Ministry of Higher Education and Research, Rennes Metropole, through the CPER Project SOPHIE/STIC Ondes, Nantes Université (NU)-Université de Rennes 1 (UR1), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Agence Spatiale Européenne = European Space Agency (ESA), Thales Alenia Space [Toulouse] (TAS), and THALES [France]

Subjects
Optimization, Polynomial, Materials science, 02 engineering and technology, Radiation, multiple beam antennas, 7. Clean energy, Waveguide (optics), law.invention, Reduction (complexity), Beamwidth, geometrical optics (GO), [SPI]Engineering Sciences [physics], Optics, law, Side lobe, 0202 electrical engineering, electronic engineering, information engineering, Range (statistics), parallel plate waveguide (PPW), Electrical and Electronic Engineering, Delays, Lenses, ray tracing, business.industry, constrained lens, 020206 networking & telecommunications, Beamformer, Lens (optics), Optical waveguides, Europe, Manufacturing, Feeds, business
Abstract

International audience; In this paper, shaped continuous parallel plate waveguide delay lenses are proposed. The previous configurations introduced by the authors displayed a residual side lobe imbalance, showing the limitations of elliptical delay lens profiles, derived from a starting bifocal constrained lens. Polynomial profiles are proposed here as a way to enhance the scanning performance and the pattern shape. Optimized configurations demonstrate a reduction in the phase aberration levels over a large scanning range ([-30, 30]). The associated radiation patterns demonstrate lower and more balanced first side lobe levels (SLLs) ( $\cong -18$ dB), as compared to the previous elliptical approach ( $\cong -13.2$ dB). A validation has been proposed through the manufacturing and test of a prototype over the down-link Ka-band ([27.5-31] GHz). Excellent radiation performance [half-power beamwidth (HPBW), SLL] has been experimentally obtained over a wide angular range ([-31.5, 31.5]), including low scanning loss and high radiation stability over the entire frequency range. High radiation efficiencies are demonstrated with this fully metallic design, particularly suitable for space applications. The mechanical simplicity offered by the concept is also quite attractive for low-cost multi-beam platforms.

Published
2019

4. Analytical Model and Study of Continuous Parallel Plate Waveguide Lens-like Multiple-Beam Antennas

Author

Etienne Girard, Ronan Sauleau, Francois Doucet, Herve Legay, Nelson J. G. Fonseca, Institut d'Électronique et des Technologies du numéRique (IETR), Université de Nantes (UN)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), European Space Agency (ESA), Thales Alenia Space (TAS), THALES, European Space Agency, Thales Alenia Space, France, in the frame of ESA’s Networking/Partnering Initiative, Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Agence Spatiale Européenne = European Space Agency (ESA), Thales Alenia Space [Toulouse] (TAS), THALES [France], and Nantes Université (NU)-Université de Rennes 1 (UR1)

Subjects
Computer science, Acoustics, Phase (waves), 02 engineering and technology, law.invention, geometrical optics (GO), [SPI]Engineering Sciences [physics], law, 0202 electrical engineering, electronic engineering, information engineering, Performance prediction, parallel plate waveguide (PPW), Electrical and Electronic Engineering, Geometrical optics, ray tracing, Numerical analysis, 020208 electrical & electronic engineering, constrained lens, 020206 networking & telecommunications, Beamformer, phase aberrations, elliptical curved linear array, Lens (optics), Transversal (combinatorics), multiple-beam antennas, Ray tracing (graphics), Reduction (mathematics)
Abstract

International audience; An analytical model based on geometrical optics is proposed to design and analyze continuous parallel plate waveguide (PPW) lens-like antennas. The proposed design is based on a transversal PPW section working as a lens-like beamformer. By simplifying the propagation inside this transversal section, a bifocal constrained lens model is first defined; it provides a relevant starting point to design the proposed beamformer. A refined model based on ray tracing and with an enhanced performance prediction is achieved by accounting the wave propagation inside the transversal cavity. The numerical analysis of phase aberrations and radiation demonstrate the performance of the proposed beamformer. The results of the ray-Tracing model are in a very good agreement with the corresponding full-wave model, while providing a significant reduction in the computational effort, making the proposed model more suitable for advanced optimization processes. © 1963-2012 IEEE.

Published
2018

5. Comparison of Optimization Procedures for the Design of Continuous Parallel Plate Waveguide Multiple Beam Lens Antennas

Author

Nelson J. G. Fonseca, Etienne Girard, Francois Doucet, Ronan Sauleau, H. Legay, Institut d'Électronique et des Technologies du numéRique (IETR), Nantes Université (NU)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), European Space Agency (ESA), Thales Alenia Space (TAS), THALES, European Space Agency, ESAEcological Society of America, ESA, Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Agence Spatiale Européenne = European Space Agency (ESA), Thales Alenia Space [Toulouse] (TAS), THALES [France], and Université de Nantes (UN)-Université de Rennes 1 (UR1)

Subjects
Optimization, Materials science, business.industry, 020208 electrical & electronic engineering, Lens antennas, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, Ray tracing, 020206 networking & telecommunications, Beamformer, 02 engineering and technology, Parallel plate waveguide, Delay lens, Geometrical optics, Parallel plate, [SPI]Engineering Sciences [physics], Optics, 0202 electrical engineering, electronic engineering, information engineering, Waveguide (acoustics), Multiple beam, business, Multiple beam antenna
Abstract

International audience; This paper proposes a comparison between two optimization procedures for the design of continuous parallel plate waveguide multiple beam lens-like antennas. A phase-only approach is first considered and the design is analyzed in terms of angular scanning performances. A pattern-based optimization is then described, taking into account both phase and amplitude effects on the outer lens contour. Comparisons between the procedures are finally provided leading to conclusions on the potential of the proposed beamformer concept. © 2018 Institution of Engineering and Technology.All Rights Reserved.

Published
2018

6. Analysis and design of a continuous parallel plate waveguide multiple beam lens antenna at Ku-band

Author

Etienne Girard, Herve Legay, Ronan Sauleau, Nelson J. G. Fonseca, Francois Doucet, Institut d'Électronique et des Technologies du numéRique (IETR), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Nantes Université (NU)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), and Université de Nantes (UN)-Université de Rennes 1 (UR1)

Subjects
0301 basic medicine, Engineering, Phase (waves), Physics::Optics, geometrical optics, 02 engineering and technology, Radiation, Ku band, law.invention, [INFO.INFO-NI]Computer Science [cs]/Networking and Internet Architecture [cs.NI], 03 medical and health sciences, Optics, law, 0202 electrical engineering, electronic engineering, information engineering, antenna design, Ideal (set theory), ray tracing, business.industry, constrained lens, 020206 networking & telecommunications, Parallel plate, [SPI.TRON]Engineering Sciences [physics]/Electronics, Lens (optics), 030104 developmental biology, beamformer, linear array, line source, Ray tracing (graphics), business, parallel plate waveguide, Waveguide
Abstract

International audience; This paper presents the description and analysis of a continuous parallel plate waveguide (PPW) lens-like beamformer. The main design parameters of the continuous delay lens are defined starting from an ideal bifocal constrained lens. A dedicated ray tracing analysis tool is developed to better describe propagation effects in the delay lens and provide more insight on phase aberrations versus pointing angle. Numerical results of a specific design at Ku-band are reported by comparing radiation patterns obtained with the ray tracing tool and a full-wave method. These results are also compared to the ideal bifocal constrained lens design. © 2017 Euraap.

Published
2017

7. Réflexion du moment présent

Author

François Doucet and François Doucet

Abstract

Réflexions du moment présent est un recueil de pensées inspirantes, riches de sagesse et d'amour. Le sens profond de ces réflexions quotidiennes nous oriente dans la bonne direction et nous ramène à ce qu'il y a de meilleur en nous. Imprégnez-vous chaque jour d'une pensée ; méditez sur sa signification et intégrez-la à vos activités tout au long de la journée.

Published
2013

8. Miguël - Les yeux de l'intérieur

Author

François Doucet and François Doucet

Abstract

«Comment mes peurs peuvent-elles devenir mes amies?» «Les peurs nous enseignent à être fort, à avoir confiance en soi, à nous dépasser, à aller plus loin, à apprécier l'état de bien-être qui suit leur apprivoisement, à être courageux, à pousser nos possibilités au-delà de nos espoirs. Une fois que tu comprends avec ton coeur que les peurs ne sont là que pour te permettre d'aller plus loin en toi en repoussant tes limites, tu cesses de les craindre et les apprivoises doucement.» Les aventures de Miguël respirent la tendresse, l'amour et la magie. Maintenant que son coeur s'ouvre à l'amour, il est sur le point de se faire jouer un mer-veilleux tour! Un tour qui le conduira tout droit à la réalisation de ses rêves d'enfant afin de découvrir la puissance de l'amour à l'intérieur de lui. Sa route lui donnera de nouveaux yeux, «Les yeux de l'intérieur». Dans mon coeur se trouvent mes plus beaux rêves; dans ma vie ceux je crois possibles.

Published
2013

11. Emergences of New Technology for Ultrafast Automated Mineral Phase Identification and Quantitative Analysis Using the CORIOSITY Laser-Induced Breakdown Spectroscopy (LIBS) System

Author

Kheireddine Rifai, Marie-Chloé Michaud Paradis, Zofia Swierczek, François Doucet, Lütfü Özcan, Alejandro Fayad, Jing Li, and François Vidal

Subjects
LIBS, TIMA-X, supervised learning, drill core, PGE, automated mineralogy, Mineralogy, QE351-399.2
Abstract

Geochemical and mineralogical characterization studies play an important role in the definition of mineral deposits. Each mineral system has a unique set of minerals with different chemical makeup and physical properties. Platinum-group elements (PGEs), for example, are scarce resources with many applications. The optimization of extraction process efficiency is therefore crucial to prevent resource shortage and increased bulk prices. To improve the mineral liberation process, high throughput sensors must be added alongside the production line as part of fast process analysis implementation. Current analytical methods are either ineffective to assess PGE content, or unusable in the conditions of the processing facilities. This article shows how Laser-induced breakdown spectroscopy (LIBS) technology, developed by ELEMISSION Inc, can circumvent these drawbacks by enabling automated, ultra-fast, and precise quantitative mineral analyses in any working environment. The drill core samples that were used in this study were collected at the Stillwater platinum group element mine in the United States. The data used for the mineralogical database was validated using the TESCAN Integrated Mineral Analyzer (TIMA) instrument.

Published
2020
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