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1. Evidence for B Cell Exhaustion in Chronic Graft-versus-Host Disease

Author

Ahmad Khoder, Abdullah Alsuliman, Rafet Basar, Catherine Sobieski, Kayo Kondo, Amin Majid Alousi, Richard Szydlo, Muharrem Muftuoglu, Hila Shaim, Jane F. Apperley, Elif Gokdemir, Nichola Cooper, Rohtesh S. Mehta, David Marin, Richard Champlin, Elizabeth Shpall, and Katayoun Rezvani

Subjects
chronic graft-versus-host disease, CD19+CD21−CD27−CD10− cells, exhausted B cells, stem cell transplantation, CD21– B cells correlate with cGVHD severity, Immunologic diseases. Allergy, RC581-607
Abstract

Chronic graft-versus-host disease (cGvHD) remains a major complication of allogeneic hematopoietic stem cell transplantation (HSCT). A number of studies support a role for B cells in the pathogenesis of cGvHD. In this study, we report the presence of an expanded population of CD19+CD21− B cells with features of exhaustion in the peripheral blood of patients with cGvHD. CD21− B cells were significantly increased in patients with active cGvHD compared to patients without cGvHD and healthy controls (median 12.2 versus 2.12 versus 3%, respectively; p

Published
2018
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2. Leukemia-induced phenotypic and functional defects in natural killer cells predict failure to achieve remission in acute myeloid leukemia

Author

Kate Stringaris, Takuya Sekine, Ahmad Khoder, Abdullah Alsuliman, Bonnie Razzaghi, Ruhena Sargeant, Jiri Pavlu, Gill Brisley, Hugues de Lavallade, Anushruti Sarvaria, David Marin, Stephan Mielke, Jane F. Apperley, Elizabeth J. Shpall, John Barrett, and Katayoun Rezvani

Subjects
Diseases of the blood and blood-forming organs, RC633-647.5
Abstract

The majority of patients with acute myeloid leukemia will relapse, and older patients often fail to achieve remission with induction chemotherapy. We explored the possibility that leukemic suppression of innate immunity might contribute to treatment failure. Natural killer cell phenotype and function was measured in 32 consecutive acute myeloid leukemia patients at presentation, including 12 achieving complete remission. Compared to 15 healthy age-matched controls, natural killer cells from acute myeloid leukemia patients were abnormal at presentation, with downregulation of the activating receptor NKp46 (P=0.007) and upregulation of the inhibitory receptor NKG2A (P=0.04). Natural killer cells from acute myeloid leukemia patients had impaired effector function against autologous blasts and K562 targets, with significantly reduced CD107a degranulation, TNF-α and IFN-γ production. Failure to achieve remission was associated with NKG2A overexpression and reduced TNF-α production. These phenotypic and functional abnormalities were partially restored in the 12 patients achieving remission. In vitro co-incubation of acute myeloid leukemia blasts with natural killer cells from healthy donors induced significant impairment in natural killer cell TNF-α and IFN-γ production (P=0.02 and P=0.01, respectively) against K562 targets and a trend to reduced CD107a degranulation (P=0.07). Under transwell conditions, the inhibitory effect of AML blasts on NK cytotoxicity and effector function was still present, and this inhibitory effect was primarily mediated by IL-10. These results suggest that acute myeloid leukemia blasts induce long-lasting changes in natural killer cells, impairing their effector function and reducing the competence of the innate immune system, favoring leukemia survival.

Published
2014
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3. Repeated vaccination is required to optimize seroprotection against H1N1 in the immunocompromised host

Author

Hugues de Lavallade, Paula Garland, Takuya Sekine, Katja Hoschler, David Marin, Kate Stringaris, Eva Loucaides, Katherine Howe, Richard Szydlo, Ed Kanfer, Donald Macdonald, Peter Kelleher, Nichola Cooper, Ahmad Khoder, Ian H. Gabriel, Dragana Milojkovic, Jiri Pavlu, John M. Goldman, Jane F. Apperley, and Katayoun Rezvani

Subjects
Diseases of the blood and blood-forming organs, RC633-647.5
Abstract

Background In 2009 the declaration by the World Health Organization of a global pandemic of influenza-H1N1 virus led to a vaccination campaign to ensure protection for immunocompromised patients. The goal of this study was to determine the efficacy of the 2009 H1N1 vaccine in patients with hematologic malignancies.Design and Methods We evaluated humoral and cellular immune responses to 2009 H1N1 vaccine in 97 adults with hematologic malignancies and compared these responses with those in 25 adult controls. Patients received two injections of vaccine 21 days apart and the controls received one dose. Antibody titers were measured using a hemagglutination-inhibition assay on days 0, 21 and 49 after injection of the first dose. Cellular immune responses to H1N1 were determined on days 0 and 49.Results By day 21 post-vaccination, protective antibody titers of 1:32 or more were seen in 100% of controls compared to 39% of patients with B-cell malignancies (P

Published
2011
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4. Evidence for B cell exhaustion in chronic graft-versus-host disease

Author

Abdullah Alsuliman, Elif Gokdemir, Jane F. Apperley, Richard E. Champlin, Muharrem Muftuoglu, Richard Szydlo, Amin M. Alousi, Catherine Sobieski, Ahmad Khoder, Kayo Kondo, Nichola Cooper, Katayoun Rezvani, David Marin, Rafet Basar, Hila Shaim, Rohtesh S. Mehta, and Elizabeth J. Shpall

Subjects
0301 basic medicine, medicine.medical_treatment, C-C chemokine receptor type 7, Hematopoietic stem cell transplantation, CXCR3, 0302 clinical medicine, immune system diseases, hemic and lymphatic diseases, Immunology and Allergy, CD19+CD21-CD27-CD10-cells, Original Research, education.field_of_study, biology, IGM MEMORY, hemic and immune systems, medicine.anatomical_structure, exhausted B cells, CD21-B cells correlate with cGVHD severity, SURVIVAL, Life Sciences & Biomedicine, lcsh:Immunologic diseases. Allergy, EXPRESSION, chronic graft-versus-host disease, Population, Immunology, CD11c, chemical and pharmacologic phenomena, stem cell transplantation, CHRONIC GVHD, CD19, 03 medical and health sciences, BRONCHIOLITIS OBLITERANS, medicine, CD19+CD21−CD27−CD10− cells, MARROW-TRANSPLANTATION, education, B cell, CLONAL EXPANSION, Science & Technology, business.industry, medicine.disease, MIXED CRYOGLOBULINEMIA, CD21– B cells correlate with cGVHD severity, 030104 developmental biology, Graft-versus-host disease, RECONSTITUTION, biology.protein, T-CELLS, lcsh:RC581-607, business, 030215 immunology
Abstract

Chronic graft-versus-host disease (cGvHD) remains a major complication of allogeneic hematopoietic stem cell transplantation (HSCT). A number of studies support a role for B cells in the pathogenesis of cGvHD. In this study, we report the presence of an expanded population of CD19+CD21− B cells with features of exhaustion in the peripheral blood of patients with cGvHD. CD21− B cells were significantly increased in patients with active cGvHD compared to patients without cGvHD and healthy controls (median 12.2 versus 2.12 versus 3%, respectively; p

Published
2017

5. BACH2 immunodeficiency illustrates an association between super-enhancers and haploinsufficiency

Author

Mohammed F Sadiyah, Ira Palmer, Anwar A. Sayed, Ahmad Khoder, Joshua Kaufman, Warren Strober, Alejandro V. Villarino, Paul T. Wingfield, Michael Mueller, Majid Kazemian, Joshua McElwee, Ahmed N. Hegazy, Behdad Afzali, Fred P. Davis, Julia Keith, Jason D. Hughes, Hong-Wei Sun, Charlotte O'Brien, Holm H. Uhlig, Michelle A. Linterman, Yu Zhang, Arian Laurence, Nichola Cooper, John J. O'Shea, Ine Vanderleyden, Dalia Kasperaviciute, Timothy J. Aitman, Rahul Roychoudhuri, Olena Kamenyeva, Juha Grönholm, Kim Montgomery-Recht, Ivan J. Fuss, Nicholas P. Restifo, Norman R. Watts, Peter Kelleher, Jana Vandrovcova, Michael J. Lenardo, Westminster Medical School Research Trust, Imperial College Healthcare NHS Trust- BRC Funding, Leuka, Zhang, Yu [0000-0002-6904-0372], Villarino, Alejandro V [0000-0001-8068-2176], Roychoudhuri, Rahul [0000-0002-5392-1853], and Apollo - University of Cambridge Repository

Subjects
0301 basic medicine, Male, Pancytopenia, AUTOIMMUNITY, Genome-wide association study, CELL DIFFERENTIATION, Haploinsufficiency, Adrenal Cortex Hormones, Recurrence, Plasma cell differentiation, Immunology and Allergy, Respiratory Tract Infections, Immunodeficiency, Genetics, Lymphocyte differentiation, Syndrome, Middle Aged, Colitis, 3. Good health, Pedigree, TRANSCRIPTION FACTORS, Basic-Leucine Zipper Transcription Factors, PLASMA-CELL-DIFFERENTIATION, 1107 Immunology, B-CELLS, Female, FUNCTIONAL PREDICTIONS, Life Sciences & Biomedicine, Adult, Heterozygote, SUSCEPTIBILITY LOCI, SEQUENCING DATA, Fever, DATABASE, Immunology, COMMON VARIABLE IMMUNODEFICIENCY, Polymorphism, Single Nucleotide, Article, CLASSIFICATION, Autoimmune Diseases, 03 medical and health sciences, Young Adult, Lymphopenia, Journal Article, medicine, Humans, GENOME-WIDE ASSOCIATION, Gene, METAANALYSIS, Science & Technology, IDENTIFICATION, business.industry, Common variable immunodeficiency, Immunologic Deficiency Syndromes, medicine.disease, RISK LOCI, 030104 developmental biology, Mutation, Splenomegaly, Primary immunodeficiency, T-CELLS, business, Tomography, X-Ray Computed
Abstract

The transcriptional programs that guide lymphocyte differentiation depend on the precise expression and timing of transcription factors (TFs). The TF BACH2 is essential for T and B lymphocytes and is associated with an archetypal super-enhancer (SE). Single-nucleotide variants in the BACH2 locus are associated with several autoimmune diseases, but BACH2 mutations that cause Mendelian monogenic primary immunodeficiency have not previously been identified. Here we describe a syndrome of BACH2-related immunodeficiency and autoimmunity (BRIDA) that results from BACH2 haploinsufficiency. Affected subjects had lymphocyte-maturation defects that caused immunoglobulin deficiency and intestinal inflammation. The mutations disrupted protein stability by interfering with homodimerization or by causing aggregation. We observed analogous lymphocyte defects in Bach2-heterozygous mice. More generally, we observed that genes that cause monogenic haploinsufficient diseases were substantially enriched for TFs and SE architecture. These findings reveal a previously unrecognized feature of SE architecture in Mendelian diseases of immunity: heterozygous mutations in SE-regulated genes identified by whole-exome/genome sequencing may have greater significance than previously recognized.

Published
2017

6. Leukemia-induced phenotypic and functional defects in natural killer cells predict failure to achieve remission in acute myeloid leukemia

Author

Abdullah Alsuliman, Ahmad Khoder, A. John Barrett, Jiri Pavlu, Elizabeth J. Shpall, Jane F. Apperley, David Marin, Bonnie Razzaghi, Hugues de Lavallade, Kate Stringaris, Takuya Sekine, Stephan Mielke, Ruhena Sargeant, Gill Brisley, Katayoun Rezvani, and Anushruthi Sarvaria

Subjects
Adult, Cytotoxicity, Immunologic, Male, Myeloid, Biology, Immunophenotyping, Natural killer cell, Young Adult, hemic and lymphatic diseases, medicine, Humans, Indoleamine-Pyrrole 2,3,-Dioxygenase, Treatment Failure, ddc:610, Aged, Aged, 80 and over, Innate immune system, Remission Induction, Degranulation, Myeloid leukemia, Induction Chemotherapy, Articles, Hematology, Middle Aged, Prognosis, medicine.disease, Coculture Techniques, Killer Cells, Natural, Leukemia, Myeloid, Acute, Leukemia, Treatment Outcome, medicine.anatomical_structure, Case-Control Studies, Immunology, Cytokines, Receptors, Natural Killer Cell, Female, K562 cells
Abstract

The majority of patients with acute myeloid leukemia will relapse, and older patients often fail to achieve remission with induction chemotherapy. We explored the possibility that leukemic suppression of innate immunity might contribute to treatment failure. Natural killer cell phenotype and function was measured in 32 consecutive acute myeloid leukemia patients at presentation, including 12 achieving complete remission. Compared to 15 healthy age-matched controls, natural killer cells from acute myeloid leukemia patients were abnormal at presentation, with downregulation of the activating receptor NKp46 (P=0.007) and upregulation of the inhibitory receptor NKG2A (P=0.04). Natural killer cells from acute myeloid leukemia patients had impaired effector function against autologous blasts and K562 targets, with significantly reduced CD107a degranulation, TNF-alpha and IFN-gamma production. Failure to achieve remission was associated with NKG2A overexpression and reduced TNF-alpha production. These phenotypic and functional abnormalities were partially restored in the 12 patients achieving remission. In vitro co-incubation of acute myeloid leukemia blasts with natural killer cells from healthy donors induced significant impairment in natural killer cell TNF-alpha and IFN-gamma production (P=0.02 and P=0.01, respectively) against K562 targets and a trend to reduced CD107a degranulation (P=0.07). Under transwell conditions, the inhibitory effect of AML blasts on NK cytotoxicity and effector function was still present, and this inhibitory effect was primarily mediated by IL-10. These results suggest that acute myeloid leukemia blasts induce long-lasting changes in natural killer cells, impairing their effector function and reducing the competence of the innate immune system, favoring leukemia survival.

Published
2014

7. Ultra-Wideband Quasi-Yagi Circular Dipole Antenna for Wireless Applications

Author

El Sayed Ahmad, Ahmad Khoder, Floc'H, Jean Marie, 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), Nantes Université (NU)-Université de Rennes 1 (UR1), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)

Subjects
ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2013

8. Double-Ellipse Circular Array Antenna for Cellular-Phone Localization

Author

El Sayed Ahmad, Ahmad Khoder, Floc'H, Jean Marie, Morgand, P., 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), Université de Nantes (UN)-Université de Rennes 1 (UR1), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)

Subjects
ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2013

9. Broadband Quasi Yagi antenna for WiFi and WiMax applications

Author

El Sayed Ahmad, Ahmad Khoder, Floc'h, Jean Marie, 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), 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 Université de Nantes (UN)-Université de Rennes 1 (UR1)

Subjects
ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2013

10. Design of Printed Dipole Antenna with Reflector and Multi-Directors

Author

Floc'H, Jean Marie, El Sayed Ahmad, Ahmad Khoder, Denoual, Jean-Michel, Rmili, Hatem, 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), Nantes Université (NU)-Université de Rennes 1 (UR1), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)

Subjects
ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2012

11. Design of a Low Profile End-Fire Antenna

Author

El Sayed Ahmad, Ahmad Khoder, Floc'h, Jean Marie, 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
ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2012

12. Antenna Design for Autonomous Sensor Network

Author

Floc'h, Jean Marie, Kokar, Yvan, El Sayed Ahmad, Ahmad Khoder, 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
ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2012

13. Quad-Band Antenna for Mobile Communication

Author

El Sayed Ahmad, Ahmad Khoder, Floc'h, Jean Marie, Lerideau, Guillaume, 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), Institut d'Electronique et de Télécommunications de Rennes (IETR), Centre National de la Recherche Scientifique (CNRS)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-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), 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), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-Centre National de la Recherche Scientifique (CNRS), and Nantes Université (NU)-Université de Rennes 1 (UR1)

Subjects
ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2012

14. Projet GELOCOM

Author

Morgand, P., Ferreol, Anne, Lienard, M., Lemur, Dominique, Floc'h, Jean Marie, El Sayed Ahmad, Ahmad Khoder, Tenoux, Thierry, Perez-Lopez, X., Fortier, Vincente, Thales Research and Technology [Palaiseau], THALES, 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), SIRADEL, Dynamiques du droit (DD), Université Montpellier 1 (UM1)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Université Montpellier 1 (UM1), THALES [France], 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), Kervella, Katell, and Nantes Université (NU)-Université de Rennes 1 (UR1)

Subjects
ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2012

15. Wide Angular Aperture Circularly Polarized Low-Profile EBG Antenna

Author

Mohamad Hajj, Christelle Boustie, Thierry Monediere, Baptiste Palacin, Moustapha Salah Toubet, Régis Chantalat, Eric Arnaud, Ahmad Khoder El Sayed Ahmad, and Bernard Jecko

Subjects
Physics, Article Subject, Axial ratio, business.industry, 05 social sciences, Bandwidth (signal processing), 020206 networking & telecommunications, 02 engineering and technology, lcsh:HE9713-9715, Angular aperture, Optics, 0502 economics and business, 0202 electrical engineering, electronic engineering, information engineering, lcsh:Cellular telephone services industry. Wireless telephone industry, lcsh:Electrical engineering. Electronics. Nuclear engineering, Electrical and Electronic Engineering, business, lcsh:TK1-9971, 050203 business & management
Abstract

This paper describes the design of a compact and wide angular circularly polarized low-profile EBG antenna. Except at 3.7 GHz and forθlower than −25° in the plane equals to 0°, the modelized structure provides an axial ratio lower than 3 dB, over a wide angular aperture of 60° and over a bandwidth of 5.3% ([3.7 GHz–3.9 GHz]). It has a very low height of 11.9 mm (/7 at 3.8 GHz). A prototype has been manufactured, and the measured performances, considering the tolerance of the measurement base (±0.5 dB), are quite similar to the simulated ones.

Published
2012
Full Text
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16. Dual-Band Printed Dipole Antenna with Parasitic Element for Compensation of Frequency Space Attenuation

Author

Ahmad Khoder El Sayed Ahmad, Jean-Marie Floc'H, 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), Nantes Université (NU)-Université de Rennes 1 (UR1), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)

Subjects
Engineering, Coaxial antenna, business.industry, Acoustics, ComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKS, 020208 electrical & electronic engineering, Antenna measurement, Electrical engineering, 020206 networking & telecommunications, 02 engineering and technology, Antenna factor, 7. Clean energy, law.invention, Radiation pattern, Hardware_GENERAL, law, Hardware_INTEGRATEDCIRCUITS, 0202 electrical engineering, electronic engineering, information engineering, Dipole antenna, Antenna noise temperature, Antenna gain, business, Monopole antenna, ComputingMilieux_MISCELLANEOUS
Abstract

A Dual-band printed dipole antenna is proposed for 2.45 GHz Bluetooth (ISM) and wireless area network (WLAN) 5.8 GHz applications. The objective of the special design is to compensate the space attenuation difference between the frequency of 2.45 GHz and the frequency of 5.8 GHz. Like the space attenuation difference is about 3.5 dB, the studied antenna must to have 3 dB more gain at 5.8 GHz than at 2.45 GHz. The prototype is fabricated and measured, and the results are in good agreement with the simulated ones. The presented antenna achieves directional radiation in the two operating bands, and gets the performances that reflection coefficient better than -10 dB with sufficient bandwidth and gain 5-8 dB, making it suitable for the base station in wireless communications.

Published
2012

17. Design of a Coupled Antenna Array for mobile HyperLAN2 applications

Author

Marc Thevenot, Ahmad Khoder El Sayed Ahmad, Cyrille Menudier, Eric Arnaud, Majed Koubeissi, Thierry Monediere, OSA, XLIM (XLIM), and Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Engineering, business.industry, Reflective array antenna, 020208 electrical & electronic engineering, 020206 networking & telecommunications, 02 engineering and technology, Array synthesis, Antenna array, Collinear antenna array, law.invention, Radiation pattern, HyperLan applications, Sensor array, law, 0202 electrical engineering, electronic engineering, information engineering, Electronic engineering, Array gain, Dipole antenna, Electrical and Electronic Engineering, Antenna (radio), business, Mutual couplings
Abstract

International audience; This paper describes the design of a 12-monopole linear array to perform a radiation pattern in the array alignment plane. This antenna can be used for HyperLAN2 telecommunications in transit vehicles. The design is based on a rigorous method which synthesizes the feeds weights by considering the strong cumulative coupling between monopoles. The originality of this paper consists in considering the couplings to obtain the objective pattern. Without this approach, a significant performance alteration is observed. The array and the feed network have been designed and successfully measured.

Published
2011

18. Switchable and beams sectorial antenna using electromagnetic band GAP surfaces

Author

Lerideau, Guillaume, Tarot, Anne-Claude, Floc'h, Jean Marie, Loison, Renaud, Thizon, S., Pied, Samuel, El Sayed Ahmad, Ahmad Khoder, Institut d'Electronique et de Télécommunications de Rennes (IETR), Centre National de la Recherche Scientifique (CNRS)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-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), 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), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-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 Université de Nantes (UN)-Université de Rennes 1 (UR1)

Subjects
ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2011

19. Design of Planar Multifonction Antenna

Author

El Sayed Ahmad, Ahmad Khoder, Thevenot, Marc, Toubet, M.S., Floc'h, Jean Marie, Lerideau, Guillaume, 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), Université de Lille, Sciences et Technologies, Institut d'Electronique et de Télécommunications de Rennes (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)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-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), Centre National de la Recherche Scientifique (CNRS)-Ecole Supérieure d'Electricité - SUPELEC (FRANCE)-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 Nantes Université (NU)-Université de Rennes 1 (UR1)

Subjects
ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2011

20. Synthesis an desing of a hybrid antenna for WIMAW

Author

El Sayed Ahmad, Ahmad Khoder, Thevenot, Marc, Salah Toubet, Moustapha, Floc'h, Jean Marie, Maury, Véronique, OSA, XLIM (XLIM), and Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2011

21. Development of an Electromagnetic Macro-model for Reconfigurable Array Application

Author

Zakka El Nashef, Georges, Torres, François, El Sayed Ahmad, Ahmad Khoder, Monédière, Thierry, Thevenot, Marc, Mons, Sébastien, Ngoya, Edouard, Quéré, Raymond, Leroy, Patricia, OSA, XLIM (XLIM), Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS), and C2S2

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

International audience; This paper presents the development and the experimental characterization of an electromagnetic array macro-model, taking into account the strong mutual coupling between the microstrip antennas. Without any complex electromagnetic calculation, this macro-modeling approach allows the calculation of necessary weights (amplitudes and phases), in order to obtain an optimum radiation pattern (high gain with low side lobes levels), while taking into account the calculated matching impedance (ZL≠50Ω) of each antenna in the array according to the frequency and the pointing angle.

Published
2010

22. Synthèse d'un réseau d'antennes couplées

Author

El Sayed Ahmad, Ahmad Khoder, Thevenot, Marc, Koubeissi, Majed, Arnaud, Eric, Monédière, Thierry, OSA, XLIM (XLIM), Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS), and Leroy, Patricia

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

International audience

Published
2009

23. Synthesis of An Array of Coupled Antennas

Author

El Sayed Ahmad, Ahmad Khoder, Thevenot, Marc, Koubeissi, Majed, Arnaud, Eric, Monédière, Thierry, Leroy, Patricia, OSA, XLIM (XLIM), and Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)

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

International audience

Published
2009

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