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125 results on '"Gillard, Raphael"'

1. RCS reduction method with anomalous reflection metasurfaces using Floquet analysis : design modelling and measurement

Author

Elineau, Matthieu, Loison, Renaud, Méric, Stéphane, Gillard, Raphaël, Pagani, Pascal, Mazé-Merceur, Geneviève, and Pouliguen, Philippe

Subjects
Physics - Applied Physics, Electrical Engineering and Systems Science - Signal Processing, Physics - Optics
Abstract

This letter proposes the design and measurement of a periodic metasurface that achieves anomalous reflection with reduced RCS in a given direction. A previous study proposed a semi-analytical model to predict the RCS behaviour of such a metasurface. This work focuses the discussion on manufacturing and measurement issues. The synthesis, design specifications, fabrication method and experimental setup are presented and discussed. Measurement results are also examined in detail, highlighting some limitations in metasurfaces RCS measurements. The proposed metasurface effectively achieves the predicted RCS level reduction in the Floquet direction considered. The agreement between simulation and experimental results demonstrates the accuracy of the modelling and the efficiency of the optimisation procedure.

Published
2023

2. Extension of Indoor MmW Link Radio Coverage in Non-line-of-Sight Conditions

Author

Dieng, Mbissane, Zaharia, Gheorghe, Zein, Ghaïs El, Gillard, Raphaël, Loison, Renaud, Celebi, Emre, Series Editor, Chen, Jingdong, Series Editor, Gopi, E. S., Series Editor, Neustein, Amy, Series Editor, Liotta, Antonio, Series Editor, Di Mauro, Mario, Series Editor, El Ghzaoui, Mohammed, editor, Das, Sudipta, editor, Samudrala, Varakumari, editor, and Medikondu, Nageswara Rao, editor

Published
2024
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11. Wideband 3-D-Printed Metal-Only Reflectarray for Controlling Orthogonal Linear Polarizations

Author

Palomares-Caballero, Angel, Molero, Carlos, Padilla, Pablo, Garcia-Vigueras, Maria, and Gillard, Raphael

Abstract

This article presents a metal-only reflectarray that enables the control of incident orthogonal polarizations in a large bandwidth. The proposed reflectarray is based on a unit cell whose tuning elements allow the independent control of the reflection phase value for the vertical and horizontal impinging polarizations. Due to the symmetry of the unit cell, the same performance is produced by each polarization when its reflection phase response is modified. The proposed unit cell provides a fairly linear phase response along the frequency with a phase variation in the orthogonal polarization of ±1°. The performance under oblique incidence and the frequency limitation of the unit cell are also investigated. From this unit cell, a metal-only reflectarray that produces circular polarization from a linear polarization is designed. The reflectarray presents a simulated directivity greater than 27 dBi with an axial ratio (AR) below 1.5 dB from 32 to 50 GHz (43.9% of bandwidth). A prototype is fabricated and the measured results agree well with the simulated ones. The obtained aperture efficiency is between 56% and 41% in the considered frequency band. The measured realized gain ranges from 27 to 30.3 dBi where the achieved radiation efficiency is greater than 97%.

Published
2023
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14. Fast optimization and sensitivity analysis of nonintuitive planar structures

Author

Cormos, Delia, Loison, Renaud, and Gillard, Raphael

Subjects
Algorithms -- Comparative analysis, Algorithm, Business, Computers, Electronics, Electronics and electrical industries
Abstract

In this paper, the new multistructure fast computation technique based on the method of moments (MoM) is applied to the optimization of printed structures with a genetic algorithm. Simultaneous analysis of different structures with the new technique leads to important time savings in comparison to an equivalent direct MoM implementation. Several structures with nonintuitive shapes are fabricated and tested. Numerical and technological sensitivities for the different realized structures are compared. The bandwidth optimization of an antenna fed by electromagnetic coupling with a microstrip line is also presented. Excellent agreement between numerical and measured results is observed. Index Terms--Fast electromagnetic (EM) optimization, method of moments (MoM), microstrip antennas.

Published
2005

18. Correction procedures for the numerical parasitic elements associated with lumped elements in global electromagnetic simulators

Author

Gillard, Raphael, Dauguet, Stephane, and Citerne, Jacques

Subjects
Electromagnetic measurements -- Models, Time-domain analysis -- Models, Numerical analysis -- Models, Integral equations -- Usage, Electronic equipment and supplies -- Analysis, Business, Computers, Electronics, Electronics and electrical industries
Abstract

This paper presents a comparative study of the treatment of lumped elements in two different full-wave electromagnetic formulations: the finite-difference time-domain (FDTD) technique and the technique of integral equations. Although these two approaches are basically different, they are seen to exhibit the same kind of numerical troubles when lumped elements are involved. More precisely, lumped elements are systematically associated with numerical parasitic elements that can seriously alter the calculated results. As a solution, this paper proposes a general alternative formulation, which permits one to suppress these numerical parasites. This formulation is successfully applied to the FDTD technique. A simpler numerical deembedding procedure, which does not fundamentally transform the original formulation, is preferred for the integral-equation technique. Index Terms - Finite-difference time-domain, integral equations, lumped-circuit element, numerical deembedding.

Published
1998

19. A general treatment of matched terminations using integral equations - modeling and applications

Author

Gillard, Raphael, Corre, Jean-Herve, Drissi, M'hamed, and Citerne, Jacques

Subjects
Integral equations -- Usage, Microwave circuits -- Research, Business, Computers, Electronics, Electronics and electrical industries
Abstract

This paper presents an original approach to simulate a broadband matched load in planar structures. Theoretically, the formulation appears as an additional boundary condition in the rigorous integral equations technique, and results in a partial rearrangement of the generalized impedance matrix in the moment method resolution. Practically, it enables the whole characterization of any planar multiport discontinuity in a procedure particularly realistic in regards to experimental measurement procedures. This new refinement is demonstrated to provide a versatile and powerful tool. Some typical applications are given which illustrate its numerous capabilities. The analysis of structures as different as a shielded microstrip step and an active receiving microstrip antenna is presented and successfully compared to experiments.

Published
1994

24. Antenne Multifonction à Modulation Directe et Agilité de Faisceau

Author

OUEDRAOGO , Samir, Hinostroza , Israel, Guinvarc'H , Régis, Gillard , Raphael, Sondra, CentraleSupélec, Université Paris-Saclay (COmUE) (SONDRA), ONERA-CentraleSupélec-Université Paris Saclay (COmUE), 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), Laboratoire franco-singapourien de recherche en électromagnétisme et radars ( SONDRA ), ONERA-SUPELEC-National University of Singapore ( NUS ) -DSO National Laboratories-CentraleSupélec, Institut d'Electronique et de Télécommunications de Rennes ( 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 ) -CentraleSupélec-Centre National de la Recherche Scientifique ( CNRS ), 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), and Nantes Université (NU)-Université de Rennes 1 (UR1)

Subjects
[SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, [ SPI.ELEC ] Engineering Sciences [physics]/Electromagnetism, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2017

34. A Multiresolution MoM Analysis of Multiport Structures Using Matched Terminations

Author

Loison, Renaud, Gillard, Raphael, Citerne, Jacques, Piton, Gerard, and Legay, H.

Subjects
Strip transmission lines -- Research, Splines -- Research, Linear systems -- Research, Electronic data processing -- Research, Magnetic dipoles -- Research, Business, Computers, Electronics, Electronics and electrical industries
Abstract

This paper presents the modeling of microstrip structures involving matched terminations with a one-dimensional multiresolution method of moment (MRMoM). Semiorthogonal spline wavelets are used as basis and testing functions. For large structures, the MRMoM generates a sparse linear system, which permits a significant reduction of the central processing unit time and of the memory storage. The modeling of matched terminations also enables a full characterization of multiport microstrip structures. Theoretical results involving microstrip dipoles are presented and compared with experiments. Index Terms--Method of moments, wavelets.

Published
2001

35. An Efficient Analysis of Planar Microwave Circuits Using A DWT-Based HAAR MRTD Scheme

Author

Carat, Guillaume, Gillard, Raphael, Citerne, Jacques, and Wiart, Joe

Subjects
Microwave wiring -- Analysis, Time-domain analysis -- Methods, Calculus -- Usage, Business, Computers, Electronics, Electronics and electrical industries
Abstract

A new wavelet-based technique to generate multiresolution time-domain schemes is presented in this paper. By using symbolic calculus, a rigorous and general formulation of subgridding at every level of multiresolution is obtained. As it is rigorously equivalent to a finer finite-difference time-domain (FDTD) scheme, it does not require any particular treatments for boundary conditions. This technique has been successfully applied to the study of microstrip structures. The near- and the far-field computation can be both improved in terms of CPU time and memory storage, while maintaining the same accuracy as the classical FDTD computation. Index Terms--Far-field computation, FDTD methods, Haar transforms, microstrip antennas, microstrip circuits, multiresolution analysis, subgridding, wavelet transforms.

Published
2000

36. Combination of DG-FDTD with a Substitution Model for Calculating Local Dosimetry in a Variable and Highly Multiscale Problem

Author

Loison Renaud, Guelilia Zakaria, Gillard Raphael, 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), 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), and Nantes Université (NU)-Université de Rennes 1 (UR1)

Subjects
[SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, Substitution model, Mathematical analysis, 0202 electrical engineering, electronic engineering, information engineering, Finite-difference time-domain method, Applied mathematics, Dosimetry, 020206 networking & telecommunications, 02 engineering and technology, Variable (mathematics), Mathematics
Abstract

International audience; This paper proposes a method to estimate human exposure to electromagnetic field radiation in a variable and highly multiscale problem. The electromagnetic field is estimated using a combination of two methods: a rigorous time domain and multiscale method, the DG-FDTD (Dual Grid Finite Difference Time Domain) and a substitution model based on the superposi- tion principle and the use of transfer functions. The association of these methods is applied to simulate a scenario involving an antenna placed on a vehicle and a human body model located around it. The purpose is to assess the electromagnetic fields in the left eye of the human body model. It is shown that this combination permits to analyse many different positions in a fast and accurate way.

Published
2014

48. Numerical modeling of an integrated multi-sector antenna using the DG-FDTD method

Author

Pascaud, Romain, Gillard, Raphael, Loison, Renaud, Le Coq, L., Thevenard, Julian, Louzir, Ali, Lo Hine Tong, Dominique, NICOLAS, Corinne, Person, Christian, Coupez, Jean-Philippe, 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), Thomson Multimedia R&D France, Thomson, Laboratoire d'Electronique et Systèmes de Télécommunications (LEST), Université de Brest (UBO)-Ecole Nationale Supérieure des Télécommunications de Bretagne-Centre National de la Recherche Scientifique (CNRS), Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO), 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), Institut de Recherche en Communications et en Cybernétique de Nantes (IRCCyN), Mines Nantes (Mines Nantes)-École Centrale de Nantes (ECN)-Ecole Polytechnique de l'Université de Nantes (EPUN), Université de Nantes (UN)-Université de Nantes (UN)-PRES Université Nantes Angers Le Mans (UNAM)-Centre National de la Recherche Scientifique (CNRS), Lab-STICC_TB_MOM_DIM, Laboratoire des sciences et techniques de l'information, de la communication et de la connaissance (UMR 3192) (Lab-STICC), Université européenne de Bretagne - European University of Brittany (UEB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Télécom Bretagne-Institut Brestois du Numérique et des Mathématiques (IBNM), Université de Brest (UBO)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-Université européenne de Bretagne - European University of Brittany (UEB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Télécom Bretagne-Institut Brestois du Numérique et des Mathématiques (IBNM), Université de Brest (UBO)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS), Département Micro-Ondes (MO), Université européenne de Bretagne - European University of Brittany (UEB)-Télécom Bretagne-Institut Mines-Télécom [Paris] (IMT), Laboratoire des sciences et techniques de l'information, de la communication et de la connaissance (Lab-STICC), Université européenne de Bretagne - European University of Brittany (UEB)-École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Télécom Bretagne-Institut Brestois du Numérique et des Mathématiques (IBNM), Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS), Nantes Université (NU)-Université de Rennes 1 (UR1), Université européenne de Bretagne - European University of Brittany (UEB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Brestois du Numérique et des Mathématiques (IBNM), Université de Brest (UBO)-Télécom Bretagne-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-Université européenne de Bretagne - European University of Brittany (UEB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Brestois du Numérique et des Mathématiques (IBNM), Université de Brest (UBO)-Télécom Bretagne-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS), École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Télécom Bretagne-Institut Brestois du Numérique et des Mathématiques (IBNM), Université de Brest (UBO)-Université européenne de Bretagne - European University of Brittany (UEB)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS), Université de Nantes (UN)-Centre National de la Recherche Scientifique (CNRS)-CentraleSupélec-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)-Université de Rennes (UNIV-RENNES)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES), and Institut Mines-Télécom [Paris] (IMT)-Télécom Bretagne-Université européenne de Bretagne - European University of Brittany (UEB)

Subjects
ComputingMilieux_MISCELLANEOUS, [SPI.TRON]Engineering Sciences [physics]/Electronics
Abstract

International audience

Published
2009

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