Download or read book Contribution l tude et la conception d une antenne r seau balayage lectronique pour liaisons de donn es haut d bit entre un drone et un satellite en bande Ka written by Thomas Lambard and published by . This book was released on 2010 with total page 231 pages. Available in PDF, EPUB and Kindle. Book excerpt: Les antennes intégrées sur des plates-formes terrestres ou aériennes seront un des points clés dans les futurs systèmes de communications par satellite. Parallèlement, l'augmentation des débits de données conjuguée à la saturation des bandes de fréquences usuelles conduit à une montée en fréquences des liaisons de données par satellites. Les travaux présentés s'inscrivent dans ce contexte, ils ont pour objet l'étude, le design et le développement d'un réseau d'antennes à balayage électronique sur drone fonctionnant à 30GHz. L'étude porte tout d'abord à la définition des caractéristiques types d'un système antennaire monté sur drone. Elle se poursuit par l'analyse, le design et la réalisation de composants du système antennaire (sources rayonnantes et déphaseurs). La dernière partie de l'étude, porte sur la mise en œuvre d'une antenne à balayage électronique fonctionnant à 30 GHz.
Download or read book CONTRIBUTION A L ETUDE DES RESEAUX PHASES ANTENNES A BALAYAGE ELECTRONIQUE DE FAISCEAUX A DIRECTIVITE VARIABLE DANS LA BANDE DES 15 GHZ written by SERGE.. GUEHO and published by . This book was released on 1990 with total page 241 pages. Available in PDF, EPUB and Kindle. Book excerpt: LE PRINCIPE, L'ETUDE THEORIQUE ET LES MESURES SUR DEUX MAQUETTES D'UNE ANTENNE RESEAU A BALAYAGE ELECTRONIQUE ET A DIRECTIVITE VARIABLE DANS LA BANDE KU FAIT L'OBJET DE LA THESE. DANS UN PREMIER TEMPS, UNE MODELISATION COMPLTE DU RESEAU PERMET D'EN CONNAITRE SES CARACTERISTIQUES RADIOELECTRIQUES. L'ETUDE THEORIQUE A MONTRE QUE LA DISPOSITION ORIGINALE DU SYSTEME D'ALIMENTATION ADOPTEE (DIVISION DE L'ANTENNE EN QUATRE SOUS-RESEAUX ET ROTATION ENTRE EUX DE 90#O) PERMETTAIT UNE AMELIORATION DES CARACTERISTIQUES DE L'ANTENNE ET NOTAMMENT UN ABAISSEMENT SENSIBLE DU NIVEAU DES LOBES SECONDAIRES. CETTE IDEE A FAIT L'OBJET DE PUBLICATION ET BREVET. UN DEPHASEUR 3 BITS, A DIODES PIN A HAUTES PERFORMANCES, NECESSAIRE AU BALAYAGE DU FAISCEAU PRINCIPAL EST ETUDIE PUIS MESURE. CE DEPHASEUR, REALISE EN LIGNES MICRORUBANS SUR UN SUBSTRAT SILICE ET FONCTIONNANT DANS LA BANDE KU, NECESSITE UN NOMBRE REDUIT DE DIODES PAR RAPPORT A DES MODELES ANTERIEURS ET N'UTILISE PAS D'AUTRES ELEMENTS LOCALISES COMME DES CAPACITES, D'OU UNE SIMPLIFICATION DU SYSTEME DE COMMANDE (BREVET ET PUBLICATION). L'ETUDE ET L'IMPLANTATION, DANS LE SYSTEME D'ALIMENTATION, DE COMMUTATEURS A DIODES PIN PERMET LA MODIFICATION DE LA DIRECTIVITE. LA SOURCE RAYONNANTE ELEMENTAIRE DU RESEAU, DEJA ETUDIEE AU LABORATOIRE, EST DEVELOPPEE DANS LA BANDE KU. DEUX MAQUETTES SONT MESUREES: LEURS CARACTERISTIQUES RADIOELECTRIQUES SONT EXCELLENTES ET CONFORMES AUX PREVISIONS THEORIQUES
Download or read book Conception d une antenne plate large bande balayage lectronique command e par incr ments de temps written by Gerrit Holtrup and published by . This book was released on 2002 with total page 398 pages. Available in PDF, EPUB and Kindle. Book excerpt: DANS LE DOMAINE DES COMMUNICATIONS PAR SATELLITE, LES ANTENNES AUSSI BIEN DE LA CHARGE UTILE SUR SATELLITE QUE DANS LE TERMINAL TERRESTRE DEVIENNENT DE PLUS EN PLUS SOPHISTIQUEES AFIN DE SE CONFORMER AUX EXIGENCES ACCRUES DE NOUVEAUX SYSTEMES MIS EN ORBITE. POUR DES SATELLITES EN DEHORS DE L'ORBITE GEOSTATIONNAIRE, IL FAUT ETRE CAPABLE DE SUIVRE LA TRAJECTOIRE DU SATELLITE DEFILANT ; POUR UN TERMINAL EN RECEPTION MULTI-SATELLITES, ON VEUT ETRE CAPABLE DE COMMUTER RAPIDEMENT ENTRE PLUSIEURS POSITIONS ORBITALES. DANS LES DEUX SITUATIONS, ON A BESOIN D'UNE ANTENNE DONT LA DIRECTION DE VISEE EST MODIFIABLE RAPIDEMENT. C'EST LE CAS D'UNE ANTENNE A BALAYAGE ELECTRONIQUE. DANS CE MEMOIRE LES DIFFERENTES ETAPES LORS DE LA CONCEPTION D'UNE ANTENNE RESEAU A ANTENNES DU TYPE PAVE MICRORUBAN SONT DECRITES. LA DIRECTION DU LOBE PRINCIPAL DE L'ANTENNE EST COMMANDABLE DE FAÇON ELECTRONIQUE. LA COMMANDE DES RADIATEURS ELEMENTAIRES SE FAIT UNIQUEMENT SUR LEURS RETARDS RELATIFS. DE DIFFERENTES DISTRIBUTIONS DE RADIATEURS ISOTROPES ONT ETE ETUDIEES A TRAVERS LEURS FACTEURS DE RESEAU ET LE NOMBRE MINIMAL D'ANTENNES AINSI QUE LEUR ARRANGEMENT SUR UN SUPPORT DONNE ONT ETE DEDUITS EN FONCTION DES PROPRIETES DESIREES DE L'ANTENNE. IL S'AVERE AVANTAGEUX D'UTILISER DES MAILLAGES NON-REGULIERS SUR DES ANNEAUX CONCENTRIQUES QUI REMPLACENT DES MAILLAGES DE TYPE RECTANGULAIRE OU TRIANGULAIRE. A PARTIR D'UNE ETUDE BIBLIOGRAPHIQUE SUR PLUSIEURS REALISATIONS PHYSIQUES DES ANTENNES A PAVE ET DE LEUR ALIMENTATION, UNE ANTENNE LARGE BANDE A POLARISATION CIRCULAIRE A ETE RETENUE. ELLE EST ALIMENTEE PAR FENTE. DES TRANSITIONS D'UNE LIGNE TRIPLAQUE ALIMENTANT L'ANTENNE VERS UN CABLE COAXIAL ONT ETE CONÇUES ET MESUREES. POUR UN POINTAGE STABLE DU FAISCEAU DANS LA DIRECTION DE VISEE, IL FAUT IMPLEMENTER UNE REALISATION DU RETARD COMPLET ENTRE LES ELEMENTS DU RESEAU. DANS CE BUT, UNE METHODE DE REALISATION LARGE BANDE DES RETARDS PAR UN RESEAU D'ECHANTILLONNAGE DES SIGNAUX ELEMENTAIRES EST PROPOSEE.
Download or read book CONTRIBUTION A L ETUDE D UN RESEAU D ANTENNES IMPRIMEES ACTIVES POUR LES LIAISONS MOBILE SATELLITE written by PHILIPPE.. DUFRANE and published by . This book was released on 1992 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt: CETTE ETUDE EST PRINCIPALEMENT DESTINEE A MONTRER L'INTERET DE L'ASSOCIATION D'UNE ANTENNE IMPRIMEE ET D'UN CIRCUIT ACTIF EN TECHNOLOGIE DES M.M.I.C.S AU SEIN D'UN MEME DISPOSITIF RAYONNANT, EN PARTICULIER POUR LES SYSTEMES DE COMMUNICATIONS ENTRE MOBILES ET SATELLITES. LES ASPECTS EMISSIONS ET RECEPTION SONT DISSOCIES, LES PARAMETRES D'ANTENNE A OPTIMISER ETANT DIFFERENTS DANS CES DEUX CAS. APRES LA CARACTERISATION ET LA JUSTIFICATION DU CHOIX DE L'AERIEN IMPRIME RETENU: L'ANTENNE PLAQUE ANNULAIRE, NOUS MONTRONS, LORS D'UNE ETUDE EN EMISSION, QUE L'UTILISATION D'UN CIRCUIT ACTIF MONOLITHIQUE SIMPLE PEUT PERMETTRE DE GENERER UNE POLARISATION CIRCULAIRE PURE SUR UN TRES LARGE ANGLE SOLIDE. EN RECEPTION, NOUS PROPOSONS UN RESEAU D'ANTENNES ACTIVES A POINTAGE ELECTRONIQUE COMME SYSTEME RAYONNANT DESTINE AUX MOBILES. DANS UN PREMIER TEMPS, NOUS METTONS EN EVIDENCE L'INFLUENCE DES PERTES DIELECTRIQUES DU SUBSTRAT ET DES DIMENSIONS REDUITES DU PLAN DE MASSE SUR LE COUPLAGE ENTRE LES SOURCES RAYONNANTES. ENSUITE, NOUS MONTRONS QUE L'ORIENTATION ELECTRONIQUE DU LOBE DE RAYONNEMENT PEUT ETRE REALISEE EN RELIANT CHAQUE ELEMENT RAYONNANT DU RESEAU A UN MODULATEUR VECTORIEL QUI ASSURE DIRECTEMENT LA PONDERATION EN AMPLITUDE ET PHASE DU SIGNAL HYPERFREQUENCE ISSU DE L'AERIEN. L'EXPERIMENTATION AVEC UN RESEAU DE DEUX ANTENNES ACTIVES NOUS PERMET ENFIN DE MONTRER LA FAISABILITE D'UN TEL DISPOSITIF RAYONNANT
Download or read book Principles of Radar and Sonar Signal Processing written by Chevalier François Le and published by Artech House. This book was released on 2002 with total page 422 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NATO Glossary of Terms and Definitions written by North Atlantic Treaty Organization and published by CreateSpace. This book was released on 2013-03-08 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt: NATO Glossary of terms and definitions (English and French). Listing terms of military significance and their definitions for use in NATO.
Download or read book Dictionary of Technical Terms for Aerospace Use written by United States. National Aeronautics and Space Administration. Scientific and Technical Information Division and published by . This book was released on 1965 with total page 338 pages. Available in PDF, EPUB and Kindle. Book excerpt: Brief definitions "intended to be as clear as possible to the non-expert, but accuracy has not been compromised for the sake of readability. Mathematics has been used where necessary to avoid ambiguity."--Intro. Published 1965.
Download or read book NATO Glossary of Abbreviations Used in NATO Documents and Publications written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Oxford Dictionary of English Grammar written by Bas Aarts and published by OUP Oxford. This book was released on 2014-01-16 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Oxford Dictionary of English Grammar is a straightforward and accessible A-Z guide to the diverse and often complex terminology of English grammar. It contains over 1,600 entries with clear and concise definitions, enhanced by numerous example sentences, as well as relevant quotations from the scholarly literature of the field. This second edition is written and edited by Professor Bas Aarts of University College London, writer of the acclaimed Oxford Modern English Grammar. It has been fully revised and updated, with particular attention paid to refreshing the example sentences included within the text. There are over 150 new entries that cover current terminology which has arisen since the publication of the first edition, and there are also new entries on the most important English grammars published since the start of the 20th century. Hundreds of new cross-references enhance the user-friendly nature of the text, and the list of works cited has been thoroughly updated to reflect the current state of the field. A short appendix of web links has been added. All in all, this Dictionary is an invaluable guide to English grammar for all students and teachers of the subject, as well as all those with an informed interest in the English language.
Download or read book Modern Radar Detection Theory written by Antonio De Maio and published by IET. This book was released on 2015-11-25 with total page 395 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modern radar detection is the new frontier for advanced radar systems capable of operating in challenging scenarios with a plurality of interference sources, both manmade and natural. Written by top researchers and recognized leaders in the field, this is the first book to provide a comprehensive understanding of the current research trends in modern radar detection. It updates readers with the latest radar signal processing algorithms now capable with high-speed computer chips and sophisticated programs. It also includes examples and applications from real systems. This is essential reading for radar systems design engineers within aerospace companies, military radar engineers, and aerospace contractors/consultants.
Download or read book Naval Arctic Manual written by and published by . This book was released on 1990 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Penguin Guide to Punctuation written by R L Trask and published by Penguin UK. This book was released on 2019-06-13 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Penguin Guide to Punctuation is indispensable for anyone who needs to get to grips with using punctuation in their written work. Whether you are puzzled by colons and semicolons, unsure of where commas should go or baffled by apostrophes, this jargon-free, succinct guide is for you.
Download or read book A Dictionary of Grammatical Terms in Linguistics written by R.L. Trask and published by Routledge. This book was released on 2013-04-15 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dictionary of grammatical terms covers both current and traditional terminology in syntax and morphology. It includes descriptive terms, the major theoretical concepts of the most influential grammatical frameworks, and the chief terms from mathematical and computational linguistics. It contains over 1500 entries, providing definitions and examples, pronunciations, the earliest sources of terms and suggestions for further reading, and recommendations about competing and conflicting usages. The book focuses on non-theory-boumd descriptive terms, which are likely to remain current for some years. Aimed at students and teachers of linguistics, it allows a reader puzzled by a grammatical term to look it up and locate further reading with ease.
Download or read book Usage and Abusage written by Eric Partridge and published by W. W. Norton & Company. This book was released on 1997 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt: A handbook of advice on the proper use of the English language. Includes a section on vogue words that have acquired a power and influence beyond what they originally possessed.
Download or read book Scientific Canadian Mechanics Magazine and Patent Office Record written by Canada. Patent Office and published by . This book was released on 1966-03 with total page 1070 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Cassell Guide to Common Errors in English written by Harry Blamires and published by Burns & Oates. This book was released on 1999 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt: The English language is a minefield of common errors and disputed points. Dealing with wide-ranging problems of grammar, syntax, punctuation, spelling, usage and style, all articles in this book have examples of incorrect usage, drawn from contemporary sources.
Download or read book Advanced Ultrawideband Radar written by James D. Taylor and published by CRC Press. This book was released on 2016-12-19 with total page 494 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the latest theory, developments, and applications related to high resolution materials-penetrating sensor systems. An international team of expert researchers explains the problems and solutions for developing new techniques and applications. Subject areas include ultrawideband (UWB) signals propagation and scattering, materials-penetrating radar techniques for small object detection and imaging, biolocation using holographic techniques, tomography, medical applications, nondestructive testing methods, electronic warfare principles, through-the-wall radar propagation effects, and target identification through measuring the target return signal spectrum changes.
