Andre Barka - Academia.edu (original) (raw)
Papers by Andre Barka
HAL (Le Centre pour la Communication Scientifique Directe), May 24, 2022
HAL (Le Centre pour la Communication Scientifique Directe), 2012
Design of artificial materials or radiating element mock-up need a specific effort for full wave ... more Design of artificial materials or radiating element mock-up need a specific effort for full wave modeling. Due to the heterogeneity of the structure, Finite Element Method is chosen. A high performance solver based on FETI Method is developed and applied to an X band EBG material.
HAL (Le Centre pour la Communication Scientifique Directe), Aug 1, 2015
We present in this work a comprehensive analytical model of a self-complementary connected array ... more We present in this work a comprehensive analytical model of a self-complementary connected array antenna. This circuit model is used to dimension and optimize the structure with a minimum computational burden. The final design involves a meta-surface on top of the radiating aperture, together with a substrate made from an artificial anisotropic dielectric. This multilayer achieves a reflection coefficient |S11|<-10dB over a 5:1 bandwidth ratio for incidences as high as 60° in both TE and TM polarizations.
HAL (Le Centre pour la Communication Scientifique Directe), Jun 1, 2018
HAL (Le Centre pour la Communication Scientifique Directe), May 1, 2017
HAL (Le Centre pour la Communication Scientifique Directe), Oct 1, 2018
HAL (Le Centre pour la Communication Scientifique Directe), Jun 1, 2015
ABSTRACT Nous présentons les résultats obtenus dans le cadre du projet SAFAS (Surface Auto- compl... more ABSTRACT Nous présentons les résultats obtenus dans le cadre du projet SAFAS (Surface Auto- complémentaire à FAible Signature) portant sur la conception d’une antenne réseau connectée auto- complémentaire. Un modèle analytique robuste a été développé permettant l’optimisation du réseau pour atteindre des rapports de bande de l’ordre de 5 :1 pour des dépointages allant jusqu’à 60°. Une campagne de validation par la mesure a été conduite dans le cadre du projet, dont nous présentons quelques résultats.
HAL (Le Centre pour la Communication Scientifique Directe), Jul 1, 2014
In this paper, we present a non-overlapping domain decomposition method by integral equations in ... more In this paper, we present a non-overlapping domain decomposition method by integral equations in the frequency domain for the resolution of wave scattering from metallic objects. The objective is to use multi-domain modelling to process multi-scale structures. This method is flexible thanks to an independance between sub-domains and relying on the local resolution of these sub-domains. Moreover, the convergence is improved compared to a classical resolution. This method is achieved for predicting radar cross-sections, studying antennas radiation and EMC applications.
HAL (Le Centre pour la Communication Scientifique Directe), Jun 8, 2022
In active transmitting arrays, high-power amplifiers (HPA) are conveniently used to provide micro... more In active transmitting arrays, high-power amplifiers (HPA) are conveniently used to provide microwave power at the input of each radiating element. They are generally connected to the radiating elements through isolators, designed to reduce the influence of the surroundings on the amplifiers load. Load-pull effects may indeed affect the transfer characteristics of HP As and even destroy them above excessive
HAL (Le Centre pour la Communication Scientifique Directe), Jul 23, 2019
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
Recently the performances of radar absorbing materials have been extended by designing new thin s... more Recently the performances of radar absorbing materials have been extended by designing new thin structures with wideband properties and large angles of incidence. In this paper, the design and performances of such ultrawideband microwave absorber of low thickness material developed within the framework of the SAFAS project (self-complementary surface with low signature) are confirmed with complementary quasi monostatic measurements and finite array simulations using Finite Element Tearing and Interconnecting domain decomposition methods (FETI).
IEEE Antennas and Propagation Society International Symposium. 1999 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.99CH37010)
ABSTRACT
This paper deals with the problem of the coupling due to the electromagnetic interactions between... more This paper deals with the problem of the coupling due to the electromagnetic interactions between array antennas and the structure of an aircraft. The objective is to propose a methodology to insure good performances of direction finding by limiting as much as possible the effects of coupling. The context is Electronic Support Measures (ESM), and we consider a large interferometer array in order to obtain a high precision goniometry of emitters on the ground. The goal of the methodology is to define the geometry of the interferometer - the position of the antennas - that limits as much as possible the effects of electromagnetic coupling.
IEEE Antennas and Wireless Propagation Letters, 2008
The design of array antennas including nonlinear devices requires specific simulation tools. Thes... more The design of array antennas including nonlinear devices requires specific simulation tools. These tools should combine the electromagnetic modeling of passive components with an appropriate description of nonlinearities potentially induced by the active circuitry. An iterative approach is proposed here for the simulation of transmitting arrays, including power amplifiers, taking into account distortion and varying antenna loads induced by coupling
Http Www Theses Fr, 1990
La premiere partie de cette these est consacree a l'etude de la diffusion de naphtol dans un ... more La premiere partie de cette these est consacree a l'etude de la diffusion de naphtol dans un cristal de naphtalene a forte densite de dislocations. Nous rappelons alors des resultats d'homogeneisation sur le probleme parabolique non lineaire qui est alors approche par une methode d'elements finis en espace et d'euler retrograde linearisee en temps. Des estimations d'erreur sont obtenues. Dans une seconde partie, nous montrons les difficultes rencontrees dans les equations de l'acoustique lineaire au voisinage d'un dioptre. Une nouvelle methode permettant de traiter les interfaces est proposee et des resultats numeriques en dimension un et deux sont obtenus
HAL (Le Centre pour la Communication Scientifique Directe), May 24, 2022
HAL (Le Centre pour la Communication Scientifique Directe), 2012
Design of artificial materials or radiating element mock-up need a specific effort for full wave ... more Design of artificial materials or radiating element mock-up need a specific effort for full wave modeling. Due to the heterogeneity of the structure, Finite Element Method is chosen. A high performance solver based on FETI Method is developed and applied to an X band EBG material.
HAL (Le Centre pour la Communication Scientifique Directe), Aug 1, 2015
We present in this work a comprehensive analytical model of a self-complementary connected array ... more We present in this work a comprehensive analytical model of a self-complementary connected array antenna. This circuit model is used to dimension and optimize the structure with a minimum computational burden. The final design involves a meta-surface on top of the radiating aperture, together with a substrate made from an artificial anisotropic dielectric. This multilayer achieves a reflection coefficient |S11|<-10dB over a 5:1 bandwidth ratio for incidences as high as 60° in both TE and TM polarizations.
HAL (Le Centre pour la Communication Scientifique Directe), Jun 1, 2018
HAL (Le Centre pour la Communication Scientifique Directe), May 1, 2017
HAL (Le Centre pour la Communication Scientifique Directe), Oct 1, 2018
HAL (Le Centre pour la Communication Scientifique Directe), Jun 1, 2015
ABSTRACT Nous présentons les résultats obtenus dans le cadre du projet SAFAS (Surface Auto- compl... more ABSTRACT Nous présentons les résultats obtenus dans le cadre du projet SAFAS (Surface Auto- complémentaire à FAible Signature) portant sur la conception d’une antenne réseau connectée auto- complémentaire. Un modèle analytique robuste a été développé permettant l’optimisation du réseau pour atteindre des rapports de bande de l’ordre de 5 :1 pour des dépointages allant jusqu’à 60°. Une campagne de validation par la mesure a été conduite dans le cadre du projet, dont nous présentons quelques résultats.
HAL (Le Centre pour la Communication Scientifique Directe), Jul 1, 2014
In this paper, we present a non-overlapping domain decomposition method by integral equations in ... more In this paper, we present a non-overlapping domain decomposition method by integral equations in the frequency domain for the resolution of wave scattering from metallic objects. The objective is to use multi-domain modelling to process multi-scale structures. This method is flexible thanks to an independance between sub-domains and relying on the local resolution of these sub-domains. Moreover, the convergence is improved compared to a classical resolution. This method is achieved for predicting radar cross-sections, studying antennas radiation and EMC applications.
HAL (Le Centre pour la Communication Scientifique Directe), Jun 8, 2022
In active transmitting arrays, high-power amplifiers (HPA) are conveniently used to provide micro... more In active transmitting arrays, high-power amplifiers (HPA) are conveniently used to provide microwave power at the input of each radiating element. They are generally connected to the radiating elements through isolators, designed to reduce the influence of the surroundings on the amplifiers load. Load-pull effects may indeed affect the transfer characteristics of HP As and even destroy them above excessive
HAL (Le Centre pour la Communication Scientifique Directe), Jul 23, 2019
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
Recently the performances of radar absorbing materials have been extended by designing new thin s... more Recently the performances of radar absorbing materials have been extended by designing new thin structures with wideband properties and large angles of incidence. In this paper, the design and performances of such ultrawideband microwave absorber of low thickness material developed within the framework of the SAFAS project (self-complementary surface with low signature) are confirmed with complementary quasi monostatic measurements and finite array simulations using Finite Element Tearing and Interconnecting domain decomposition methods (FETI).
IEEE Antennas and Propagation Society International Symposium. 1999 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.99CH37010)
ABSTRACT
This paper deals with the problem of the coupling due to the electromagnetic interactions between... more This paper deals with the problem of the coupling due to the electromagnetic interactions between array antennas and the structure of an aircraft. The objective is to propose a methodology to insure good performances of direction finding by limiting as much as possible the effects of coupling. The context is Electronic Support Measures (ESM), and we consider a large interferometer array in order to obtain a high precision goniometry of emitters on the ground. The goal of the methodology is to define the geometry of the interferometer - the position of the antennas - that limits as much as possible the effects of electromagnetic coupling.
IEEE Antennas and Wireless Propagation Letters, 2008
The design of array antennas including nonlinear devices requires specific simulation tools. Thes... more The design of array antennas including nonlinear devices requires specific simulation tools. These tools should combine the electromagnetic modeling of passive components with an appropriate description of nonlinearities potentially induced by the active circuitry. An iterative approach is proposed here for the simulation of transmitting arrays, including power amplifiers, taking into account distortion and varying antenna loads induced by coupling
Http Www Theses Fr, 1990
La premiere partie de cette these est consacree a l'etude de la diffusion de naphtol dans un ... more La premiere partie de cette these est consacree a l'etude de la diffusion de naphtol dans un cristal de naphtalene a forte densite de dislocations. Nous rappelons alors des resultats d'homogeneisation sur le probleme parabolique non lineaire qui est alors approche par une methode d'elements finis en espace et d'euler retrograde linearisee en temps. Des estimations d'erreur sont obtenues. Dans une seconde partie, nous montrons les difficultes rencontrees dans les equations de l'acoustique lineaire au voisinage d'un dioptre. Une nouvelle methode permettant de traiter les interfaces est proposee et des resultats numeriques en dimension un et deux sont obtenus