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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

M?todo din?mico aplicado para antenas cil?ndricas

Silva Neto, Almir Souza e 28 June 2013 (has links)
Made available in DSpace on 2014-12-17T14:56:15Z (GMT). No. of bitstreams: 1 AlmirSSN_DISSERT.pdf: 1940293 bytes, checksum: 7a7b36b247a4dcfecb4c487d79d7aa31 (MD5) Previous issue date: 2013-06-28 / Nowadays there has been a major breakthrough in the aerospace area, with regard to rocket launches to research, experiments, telemetry system, remote sensing, radar system (tracking and monitoring), satellite communications system and insertion of satellites in orbit. This work aims at the application of a circular cylindrical microstrip antenna, ring type, and other cylindrical rectangular in structure of a rocket or missile to obtain telemetry data, operating in the range of 2 to 4 GHz, in S-band. Throughout this was developed just the theoretical analysis of the Transverse transmission line method which is a method of rigorous analysis in spectral domain, for use in rockets and missiles. This analyzes the spread in the direction "ρ" , transverse to dielectric interfaces "z" and "φ", for cylindrical coordinates, thus taking the general equations of electromagnetic fields in function of e [1]. It is worth mentioning that in order to obtain results, simulations and analysis of the structure under study was used HFSS program (High Frequency Structural Simulator) that uses the finite element method. With the theory developed computational resources were used to obtain the numerical calculations, using Fortran Power Station, Scilab and Wolfram Mathematica ?. The prototype was built using, as a substrate, the ULTRALAM ? 3850, of Rogers Corporation, and an aluminum plate as a cylindrical structure used to support. The agreement between the measured and simulated results validate the established processes. Conclusions and suggestions are presented for continuing this work / Nos dias atuais observa-se um grande avan?o na ?rea aeroespacial, no que se refere aos lan?amentos de foguetes, para pesquisas, experimentos, sistema de telemetria, sensoriamento remoto, sistema de radar (rastreamento e monitora??o), sistema de comunica??es via sat?lites e inser??o de sat?lites em ?rbita. Este trabalho tem como objetivo a aplica??o de uma antena de microfita cil?ndrica circular, tipo anel, e outra retangular cil?ndrica na estrutura de um foguete ou m?ssel para obten??o de dados de telemetria, operando na faixa de 2 a 4 GHz, na banda S. Ao longo deste foi desenvolvida apenas a an?lise te?rica do M?todo da Linha de Transmiss?o Transversa que ? um m?todo de an?lise rigoroso no dom?nio espectral, para aplica??o em foguetes e m?sseis. Este analisa a propaga??o na dire??o ρ , transversa ?s interfaces diel?tricas z e φ , para coordenadas cil?ndricas, tendo assim as equa??es gerais dos campos eletromagn?ticos em fun??o de e [1]. Vale ressaltar que para a obten??o dos resultados, simula??es e an?lise da estrutura em estudo foi utilizado o programa HFSS (High Frequency Structural Simulator) que utiliza o M?todo dos elementos finitos. Com a teoria desenvolvida foram utilizados recursos computacionais para obten??o dos c?lculos num?ricos, atrav?s do Fortran Power Station, Scilab e o Wolfram Mathematica?. O prot?tipo foi constru?do utilizando, como substrato, o ULTRALAM? 3850, da Rogers Corporation, e uma placa de alum?nio como suporte ? estrutura cil?ndrica utilizada. A concord?ncia entre os resultados medidos e os simulados validam os processos estabelecidos. S?o apresentadas sugest?es e conclus?es para a continuidade deste trabalho
2

Antenas de microfita para 4G, 5G e arranjo de antenas cil?ndricas

Silva Neto, Almir Souza e 22 August 2016 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-02-17T19:02:33Z No. of bitstreams: 1 AlmirSouzaESilvaNeto_TESE.pdf: 7594512 bytes, checksum: e73e4bac15af98e3446fb9a14895033b (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-02-17T21:29:12Z (GMT) No. of bitstreams: 1 AlmirSouzaESilvaNeto_TESE.pdf: 7594512 bytes, checksum: e73e4bac15af98e3446fb9a14895033b (MD5) / Made available in DSpace on 2017-02-17T21:29:12Z (GMT). No. of bitstreams: 1 AlmirSouzaESilvaNeto_TESE.pdf: 7594512 bytes, checksum: e73e4bac15af98e3446fb9a14895033b (MD5) Previous issue date: 2016-08-22 / Nos dias atuais observa-se um grande avan?o na ?rea aeroespacial, em sistema de telemetria, sensoriamento remoto, sistemas de radar (rastreamento e monitora??o), sistemas de comunica??es via sat?lite e novas tecnologias de comunica??es de voz e dados. As antenas de microfita cada vez mais t?m sido utilizadas devido as suas caracter?sticas e vantagens. Dessa forma, este trabalho apresenta an?lises, simula??es e medi??es de antenas de microfitas para aplica??o em: redes locais sem fio WLAN (Wireless Local Area Network) com opera??o em 2,4 GHz; tecnologia de quarta gera??o 4G para o uso em 2,5 GHz; tecnologia de quinta gera??o 5G nas frequ?ncias de 28 GHz e 60 GHz; aplica??es em UWB (Ultra Wide Band) com bandas de rejei??o utilizando ressoadores de anel partido; sat?lites com opera??o na banda Ku e aplica??o em telemetria utilizando estruturas cil?ndricas operando na faixa de 2 a 4 GHz, na banda S. Foram feitas an?lises com aplica??o de estrutura EBG (Electromagnetic Band Gap) no substrato e no plano de terra, utiliza??o de substrato metamaterial, aplica??o de estruturas DGS (Defected Ground Strutures) no plano de terra e arranjos, com objetivo de obter melhoria nos par?metros, em especial ganho e largura de banda. O m?todo de an?lise das antenas de microfita utilizado neste trabalho foi o m?todo de Linha de Transmiss?o Transversa. Os resultados simulados foram obtidos atrav?s do software comercial Ansoft HFSS. Compara??es entre os resultados simulados e medidos das antenas propostas foram realizados para efeito de valida??o dos prot?tipos. Ao final, s?o apresentadas sugest?es para a continuidade deste trabalho. / Nowadays there has been a major breakthrough in aerospace, in telemetry system, remote sensing, radar systems (tracking and monitoring), satellite communications systems and new technologies for voice and data communications. The microstrip antennas have increasingly been used due to their characteristics and advantages. Thus, this work presents analysis, simulations and measurements of microstrip antenna for use in: wireless local area networks WLAN (Wireless Local Area Network) with operation at 2.4 GHz; fourth generation 4G technology for use in 2.5 GHz; fifth-generation technology 5G at frequencies of 28 GHz and 60 GHz; applications in UWB (Ultra Wide Band) with rejection bands using resonators party ring; satellites operating in the Ku band and application in telemetry using cylindrical structures operating at 2 to 4 GHz band, the S band. Analysis were made with application of EBG structure (Electromagnetic Band Gap) on substrate and in the ground plane, using substrate metamaterial, application DGS structures (Defected Ground Structures) in the ground plane and arrangements, in order to achieve improvement in the parameters, in particular gain and bandwidth. The method of analysis of microstrip antennas used in this work was the Transverse Transmission Line method. The simulated results were obtained by Ansoft HFSS commercial software. Comparisons between simulated and measured results of the antennas proposals were made for effect of validation of the prototypes. Suggestions are made for the continuity of this work.

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