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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.
51

Three block war : en studie av utbildningsdokument

Lind, Anna January 2009 (has links)
<p>Uppsatsen är skriven som en del i de studier i krigsvetenskap jag erhållit på Yrkesofficersprogrammets sista termin.</p><p>Syftet med uppsatsen är att bidra till utvecklingen av de soldatutbildningshänvisningar som nyttjas vid Artilleriregementet. </p><p>Frågeställningarna lyder: </p><p>-          Tränas soldaterna vid Artilleriregementet, enligt utbildningsdokumenten som nyttjas, för att klara av de krav som ”Three block war” ställer? </p><p>-          Kompletteras eventuella brister vid utbildningen på Artilleriregementet, genom utbildningen som sker inför internationell tjänst? </p><p>Metoden som använts är deskription med tekniken litteraturstudier. Begreppet "Three block war" beskrivs därefter analyseras utbildningsdokumenten för att besvara frågeställningarna.  </p><p>Analysen visar att soldater som gjort värnplikten på Artilleriregementet och därefter genomgått den gemensamma utbildningen som ges utlandsstyrkan fortfarande har ett behov av utbildning. Detta kopplat till om soldaterna skall klara av att verka i ett område som karaktäriseras av "Three block war".</p>
52

Three block war : en studie av utbildningsdokument

Lind, Anna January 2009 (has links)
Uppsatsen är skriven som en del i de studier i krigsvetenskap jag erhållit på Yrkesofficersprogrammets sista termin. Syftet med uppsatsen är att bidra till utvecklingen av de soldatutbildningshänvisningar som nyttjas vid Artilleriregementet.  Frågeställningarna lyder:  -          Tränas soldaterna vid Artilleriregementet, enligt utbildningsdokumenten som nyttjas, för att klara av de krav som ”Three block war” ställer?  -          Kompletteras eventuella brister vid utbildningen på Artilleriregementet, genom utbildningen som sker inför internationell tjänst?  Metoden som använts är deskription med tekniken litteraturstudier. Begreppet "Three block war" beskrivs därefter analyseras utbildningsdokumenten för att besvara frågeställningarna.   Analysen visar att soldater som gjort värnplikten på Artilleriregementet och därefter genomgått den gemensamma utbildningen som ges utlandsstyrkan fortfarande har ett behov av utbildning. Detta kopplat till om soldaterna skall klara av att verka i ett område som karaktäriseras av "Three block war".
53

Estudo da varia??o da periodicidade e do acoplamento entre superf?cies seletivas de frequ?ncia com elementos fractais e helicoidais em estruturas de multicamadas

Trindade, Jos? Idifranse Aguiar 30 January 2015 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-04-22T21:41:53Z No. of bitstreams: 1 JoseIdifranseAguiarTrindade_TESE.pdf: 3433912 bytes, checksum: cc18488777701871fa15bf7410b660d3 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-04-22T22:05:27Z (GMT) No. of bitstreams: 1 JoseIdifranseAguiarTrindade_TESE.pdf: 3433912 bytes, checksum: cc18488777701871fa15bf7410b660d3 (MD5) / Made available in DSpace on 2016-04-22T22:05:27Z (GMT). No. of bitstreams: 1 JoseIdifranseAguiarTrindade_TESE.pdf: 3433912 bytes, checksum: cc18488777701871fa15bf7410b660d3 (MD5) Previous issue date: 2015-01-30 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Este trabalho tem como objetivo investigar o comportamento de elementos fractais e elementos helicoidais em estruturas planares de microfita. Em particular, as superf?cies seletivas de frequ?ncia (FSS) tiveram seus elementos convencionais alterados para formatos fractais e para o formato helicoidal. O substrato diel?trico usado ? de fibra de vidro (FR-4) e tem espessura de 1,5 mm, permissividade el?trica relativa de 4,4 e tangente de perdas igual a 0,02. Para as FSS, adotou-se a geometria fractal pentagonal de D?rer e a geometria helicoidal. Para efetuar as medi??es, foram utilizadas duas antenas cornetas em visada direta, conectadas por cabo coaxial a um analisador de redes vetorial. Alguns prot?tipos foram selecionados para fabrica??o e medi??o. A partir dos resultados preliminares obtidos, objetivou-se encontrar aplica??es pr?ticas para as estruturas a partir do cascateamento entre elas. Para as FSSs com elementos fractais de D?rer, observou-se um comportamento multibanda proporcionado pela geometria fractal, ao mesmo tempo em que a largura de banda se tornou estreita na medida em que o n?vel de itera??o fractal aumentou, tornando-a uma estrutura mais seletiva em frequ?ncia, com um maior fator de qualidade. Uma an?lise param?trica possibilitou a an?lise da influ?ncia da varia??o da camada de ar entre elas. As estruturas fractais pentagonais foram consideradas e cascateadas. O cascateamento entre determinadas estruturas pentagonais apresentou um comportamento tri-band para determinados valores da camada de ar entre elas, com aplica??es na banda licenciada 2,5 GHz (2,3 ~ 2,7 GHz), e 3,5 GHz (3,3 ~ 3,8 GHz). Para as FSSs com elementos helicoidais, seis estruturas foram consideradas. A partir de resultados preliminares obtidos com a an?lise isolada das estruturas, o cascateamento entre elas proporcionou o aumento da largura de banda, na medida em que a espessura da camada de ar aumenta. Com a finalidade de encontrar aplica??es pr?ticas para as estruturas helicoidais cascateadas, as estruturas propostas foram cascateadas e as mesmas encontraram aplica??es na banda-X (8,0 ~ 12,0 GHz), e na banda n?o licenciada que compreende a faixa de 5,25 a 5,85 GHz. Na caracteriza??o num?rica e experimental das estruturas abordadas, utilizou-se, respectivamente, o software comercial Ansoft Designere um analisador de redes vetorial, modelo N5230A da Agilent. / This work aims to investigate the behavior of fractal and helical elements structures in planar microstrip. In particular, the frequency selective surfaces (FSSs) had changed its conventional elements to fractal and helical formats. The dielectric substrate used was fiberglass (FR-4) and has a thickness of 1.5 mm, a relative permittivity 4.4 and tangent loss equal to 0.02. For FSSs, was adopting the D?rer?s fractal geometry and helical geometry. To make the measurements, we used two antennas horns in direct line of sight, connected by coaxial cable to the vector network analyzer. Some prototypes were select for built and measured. From preliminary results, it was aimed to find practical applications for structures from the cascading between them. For FSSs with D?rer?s fractal elements was observed behavior provided by the multiband fractal geometry, while the bandwidth has become narrow as the level of iteration fractal increased, making it a more selective frequency with a higher quality factor. A parametric analysis allowed the analysis of the variation of the air layer between them. The cascading between fractal elements structure were considered, presented a tri-band behavior for certain values of the layer of air between them, and find applications in the licensed 2.5GHz band (2.3-2.7) and 3.5GHz band (3.3-3.8). For FSSs with helical elements, six structures were considered, namely H0, H1, H2, H3, H4 and H5. The electromagnetic behavior of them was analyzed separately and cascaded. From preliminary results obtained from the separate analysis of structures, including the cascade, the higher the bandwidth, in that the thickness of the air layer increases. In order to find practical applications for helical structures cascaded, the helical elements structure has been cascaded find applications in the X-band (8.0-12.0) and unlicensed band (5.25-5.85). For numerical and experimental characterization of the structures discussed was used, respectively, the commercial software Ansoft Designer and a vector network analyzer, Agilent N5230A model.
54

M?todo h?brido para projeto de superf?cies seletivas em frequ?ncia

Ara?jo, Gilmara Linhares de 10 December 2015 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-08-09T22:51:26Z No. of bitstreams: 1 GilmaraLinharesDeAraujo_TESE.pdf: 11647948 bytes, checksum: 94a5e966f18f8dd6bfc6646d2519542b (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-08-10T23:44:37Z (GMT) No. of bitstreams: 1 GilmaraLinharesDeAraujo_TESE.pdf: 11647948 bytes, checksum: 94a5e966f18f8dd6bfc6646d2519542b (MD5) / Made available in DSpace on 2016-08-10T23:44:37Z (GMT). No. of bitstreams: 1 GilmaraLinharesDeAraujo_TESE.pdf: 11647948 bytes, checksum: 94a5e966f18f8dd6bfc6646d2519542b (MD5) Previous issue date: 2015-12-10 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Esse trabalho apresenta uma t?cnica h?brida de projeto de superf?cies seletivas em frequ?ncia, sobre uma camada diel?trica isotr?pica, considerando diversas geometrias para os elementos das c?lulas unit?rias. Especificamente, a t?cnica h?brida usa o m?todo do circuito equivalente em conjunto com algoritmos gen?ticos, visando a s?ntese de estruturas com resposta singleband e dual-band. O m?todo do circuito equivalente permite modelar a estrutura por meio de um circuito equivalente e tamb?m a obten??o de circuitos para diferentes geometrias. A partir da obten??o dos par?metros desses circuitos, podem-se obter as caracter?sticas de transmiss?o e de reflex?o das estruturas modeladas. Para obter a otimiza??o das estruturas modeladas, de acordo com a resposta em frequ?ncia desejada, a ferramenta de otimiza??o do Matlab optimtool mostrou-se de f?cil utiliza??o, permitindo explorar resultados importantes na an?lise de otimiza??o. No trabalho, s?o apresentados resultados num?ricos e experimentais para as caracter?sticas de transmiss?o de diferentes geometrias analisadas. Foram efetuadas compara??es com resultados apresentados na literatura, tendo-se observado uma boaconcord?ncia nos casos analisados para estruturas com substratos isotr?picos. / This thesis presents a hybrid technique of frequency selective surfaces project (FSS) on a isotropic dielectric layer, considering various geometries for the elements of the unit cell. Specifically, the hybrid technique uses the equivalent circuit method in conjunction with genetic algorithm, aiming at the synthesis of structures with response single-band and dual-band. The equivalent circuit method allows you to model the structure by using an equivalent circuit and also obtaining circuits for different geometries. From the obtaining of the parameters of these circuits, you can get the transmission and reflection characteristics of patterned structures. For the optimization of patterned structures, according to the desired frequency response, Matlab? optimization tool named optimtool proved to be easy to use, allowing you to explore important results on the optimization analysis. In this thesis, numeric and experimental results are presented for the different characteristics of the analyzed geometries. For this, it was determined a technique to obtain the parameter N, which is based on genetic algorithms and differential geometry, to obtain the algebraic rational models that determine values of N more accurate, facilitating new projects of FSS with these geometries. The optimal results of N are grouped according to the occupancy factor of the cell and the thickness of the dielectric, for modeling of the structures by means of rational algebraic equations. Furthermore, for the proposed hybrid model was developed a fitness function for the purpose of calculating the error occurred in the definitions of FSS bandwidths with transmission features single band and dual band. This thesis deals with the construction of prototypes of FSS with frequency settings and band widths obtained with the use of this function. The FSS were initially reviewed through simulations performed with the commercial software Ansoft Designer ?, followed by simulation with the equivalent circuit method for obtaining a value of N in order to converge the resonance frequency and the bandwidth of the FSS analyzed, then the results obtained were compared. The methodology applied is validated with the construction and measurement of prototypes with different geometries of the cells of the arrays of FSS.
55

An?lise de superf?cies seletivas de freq??ncia para aplica??es em ondas milim?tricas

Medeiros, Gilcarlos Ribeiro de 24 September 2001 (has links)
Made available in DSpace on 2014-12-17T14:55:16Z (GMT). No. of bitstreams: 1 GilcarlosRM_Capa_ate_pag35.pdf: 10181958 bytes, checksum: 87e8f1bbd9c4787bded2b91e955fbdb0 (MD5) Previous issue date: 2001-09-24 / This work consists in the development of a theoretical and numerical analysis for frequency selective surfaces (FSS) structures with conducting patch elements, such as rectangular patches, thin dipoles and cross dipoles, on anisotropic dielectric substrates. The analysis is developed for millimeter wave band applications. The analytical formulation is developed in the spectral domain, by using a rigorous technique known as equivalent transmission line method, or immitance approach. The numerical analysis is completed through the use of the Galerkin's technique in the Fourier transform domain, using entire-domain basis functions. In the last decades, several sophisticated analytical techniques have been developed for FSS structure applications. Within these applications, it can be emphasized the use of FSS structures on reflecting antennas and bandpass radomes. In the analysis, the scattered fields of the FSS geometry are related to the surface induced currents on the conducting patches. After the formulation of the scattering problem, the numerical solution is obtained by using the moment method. The choice of the basis functions plays a very important role in the numerical efficiency of the numerical method, once they should provide a very good approximation to the real current distributions on the FSS analyzed structure. Thereafter, the dyadic Green's function components are obtained in order to evaluate the basis functions unknown coefficients. To accomplish that, the Galerkin's numerical technique is used. Completing the formulation, the incident fields are determined through the incident potential, and as a consequence the FSS transmission and reflection characteristics are determined, as function of the resonant frequency and structural parameters. The main objective of this work was to analyze FSS structures with conducting patch elements, such as thin dipoles, cross dipoles and rectangular patches, on anisotropic dielectric substrates, for high frequency applications. Therefore, numerical results for the FSS structure main characteristics were obtained in the millimeter wave bando Some of these FSS characteristics are the resonant / Este trabalho consiste na an?lise te?rica e num?rica de superf?cies seletiva de freq??ncia com elementos do tipo patch retangular, dipolo fino e dipolo cruzado sobre substratos diel?tricos anisotr?picos, para a faixa de freq??ncias de ondas milim?tricas. A formula??o anal?tica ? realizada por uma t?cnica de abordagem do dom?nio espectral conhecido como m?todo de linha de transmiss?o equivalente ou m?todo da imit?ncia. A an?lise num?rica ? solucionada atrav?s do uso da t?cnica num?rica de Galerkin no dom?nio da transformada de Fourier, utilizando-se fun??es de base de dom?nio inteiro. Nas ?ltimas d?cadas, muitas aplica??es e t?cnicas anal?ticas sofisticadas t?m sido desenvolvidas para a caracteriza??o das FSS. Dentre as aplica??es, pode-se destacar a utiliza??o de FSS em antenas refletoras e em redomes passa-faixa. Primeiramente relaciona-se os campos espalhados da FSS com as correntes superficiais induzidas na patch. Ap?s a dedu??o realizada para o problema de espalhamento, pode-se obter a solu??o num?rica da mesma atrav?s do m?todo dos momentos. A escolha das fun??es de base ? de grande import?ncia para a efici?ncia num?rica do m?todo, devendo se aproximar ao m?ximo das caracter?sticas f?sica das distribui??es de corrente na estrutura analisada
56

An?lise te?rica e experimental de superf?cies seletivas de freq??ncia e suas aplica??es em antenas planares

Ara?jo, Lincoln Machado de 13 August 2009 (has links)
Made available in DSpace on 2014-12-17T14:55:39Z (GMT). No. of bitstreams: 1 LincolnMA.pdf: 1667449 bytes, checksum: b8113389f31903ba22cf94dbc22192c1 (MD5) Previous issue date: 2009-08-13 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / This work presents a theoretical and numerical analysis of structures using frequency selective surfaces applied on patch antennas. The FDTD method is used to determine the time domain reflected fields. Applications of frequency selective surfaces and patch antennas cover a wide area of telecommunications, especially mobile communications, filters and WB antennas. scattering parameters are obteained from Fourier Transformer of transmited and reflected fields in time domain. The PML are used as absorbing boundary condition, allowing the determination of the fields with a small interference of reflections from discretized limit space. Rectangular patches are considered on dielectric layer and fed by microstrip line. Frequency selective surfaces with periodic and quasi-periodic structures are analyzed on both sides of antenna. A literature review of the use of frequency selective surfaces in patch antennas are also performed. Numerical results are also compared with measured results for return loss of analyzed structures. It is also presented suggestions of continuity to this work / Este trabalho apresenta uma an?lise te?rica e num?rica de estruturas que utilizam superf?cies seletivas de frequ?ncia aplicadas a antenas do tipo patch. Para isso, ? utilizado o m?todo das diferen?as finitas no dom?nio do tempo (FDTD) visando determinar os campos refletidos a partir de uma onda plana incidente no dom?nio do tempo. As aplica??es das superf?cies seletivas de freq??ncia e antenas patch abrangem uma grande ?rea das Telecomunica??es, principalmente em comunica??es m?veis e v?o desde filtros at? as antenas banda larga. Especificamente, a an?lise usa os campos transmitidos e refletidos obtidos no dom?nio do tempo, em conjunto com transformada de Fourier permitindo a obten??o dos par?metros de transmiss?o da antena. A condi??o de contorno absorvedora utilizada foi a de camada perfeitamente casada (PML), permitindo a determina??o num?rica dos campos com uma quantidade menor de interfer?ncias provenientes de reflex?es nos limites do espa?o discretizado. S?o considerados patches retangulares condutores sobre uma camada diel?trica e alimentados por linha de microfita. Foram analisadas superf?cies seletivas de frequ?ncia peri?dicas e quase peri?dicas tanto no plano de terra quanto no plano do pr?prio patch. ? realizada uma revis?o bibliogr?fica a respeito da utiliza??o de superf?cies seletivas de frequ?ncia em antenas patch. Tamb?m s?o comparados resultados num?ricos e medidos para a perda de retorno das estruturas analisadas. S?o apresentadas, ainda, sugest?es de continuidade para este trabalho
57

Desenvolvimento de uma nova t?cnica para otimiza??o de circuitos planares inspirada no comportamento social das aranhas

Oliveira, Phelipe Sena 06 February 2017 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2018-01-23T14:13:10Z No. of bitstreams: 1 PhelipeSenaOliveira_TESE.pdf: 2369727 bytes, checksum: 2bb1dad07260b4efd645c7028636e62f (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2018-01-24T15:05:44Z (GMT) No. of bitstreams: 1 PhelipeSenaOliveira_TESE.pdf: 2369727 bytes, checksum: 2bb1dad07260b4efd645c7028636e62f (MD5) / Made available in DSpace on 2018-01-24T15:05:44Z (GMT). No. of bitstreams: 1 PhelipeSenaOliveira_TESE.pdf: 2369727 bytes, checksum: 2bb1dad07260b4efd645c7028636e62f (MD5) Previous issue date: 2017-02-06 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / As novas configura??es de dispositivos e circuitos de micro-ondas resulta em aumento de complexidade nos processos de desenvolvimento, particularmente nos casos de s?ntese. Antenas e superf?cies seletivas de frequ?ncia (Frequency Selective Surface - FSS) s?o estruturas muito importantes nos sistemas de comunica??es, que podem ser otimizadas pela atua??o dos algoritmos bioinspirados. Geralmente, para que os algoritmos bioinspirados auxiliem na otimiza??o dessas estruturas ? necess?ria a implementa??o de t?cnicas de an?lise num?rica como o M?todo dos Momentos ou Elementos Finitos. Diante da dificuldade de modelagem das t?cnicas descritas, ? comum a utiliza??o de uma fun??o de estima??o, como as Redes Neurais Artificiais, para substituir a an?lise num?rica. Embora encontre solu??es desejadas, as estima??es s?o realizadas ap?s um processo de treinamento efetuado atrav?s de uma base de dados. Cada estrutura de antena ou FSS exige uma base de dados espec?fica. Este trabalho prop?e uma t?cnica de otimiza??o baseado na utiliza??o de um algoritmo bioinspirado e um framework que realiza a integra??o do algoritmo ao software comercial ANSYS HFSS. O prop?sito ? realizar as simula??es das poss?veis solu??es durante a execu??o do algoritmo bioinspirado, e com isso, evitar o uso de uma base de dados, e assim, tornar a t?cnica eficiente e flex?vel com rela??o ?s altera??es nas estruturas de antenas ou FSS. Outro objetivo original deste trabalho ? a utiliza??o do algoritmo Social Spider Optimization ? SSO para a solu??o de problemas na ?rea de eletromagnetismo aplicado. Para comprovar a efic?cia da t?cnica proposta alguns projetos de antena e FSS s?o otimizados atrav?s de varia??es em seus par?metros estruturais. Os resultados obtidos na otimiza??o dos projetos dos circuitos s?o comparados com outras t?cnicas, tendo sido observado uma boa concord?ncia. / The new settings for devices and microwaves circuits result in an increase of complexity in the processes of development, specially in regards to the process of synthesis. Antennas and Frequency Selective Surfaces (FSS) are primordial in communication systems. Alternatively, these structures may be optimized through the usage of bio-inspired algorithms. Generally, in order for the bio-inspired algorithms to assist in the optimization of FSS structures, it is necessary to implement several numerical analysis techniques, such as the method of moments or finite elements. Because of the difficulty to model such methods, it has been turned common the usage of a point estimation function, such as artificial neural networks, to substitute the numerical analysis. Although these procedures end up encountering desirable solutions, the estimations are done after a training process conducted through a database. Additionally, every FSS antenna demands a specific database. This work proposes an optimization technique that relies on the usage of a bio-inspired algorithm and a framework (that provides the integration between the algorithm and the commercial software ANSS HFSS). The purpose of the work is to do simulations of possible solutions during the execution of the bio-inspired algorithm; therefore, avoiding the usage of the database; and so, make the technique flexible and efficient in relation to altering the antennas? structures or FSS. Furthermore, another objective of this work is the usage of the algorithm, namely Social Spider Optimization - SSO in the search for solutions in the field of applied electromagnetism. In order to prove the efficiency of the proposed techniques, some FSS? and antennas? projects are optimized through the variation of their structural parameters. In conclusion, the results that were obtained through the procedures previously shown, are compared to other techniques, resulting in a satisfying agreement rate.
58

An?lise e desenvolvimento de novas configura??es de antenas, filtros e superf?cies seletivas de frequ?ncia n?o-uniformes e reconfigur?veis pelo m?todo WCIP generalizado

Silva Neto, Valdemir Praxedes da 29 April 2016 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-01-27T12:26:54Z No. of bitstreams: 1 ValdemirPraxedesDaSilvaNeto_TESE.pdf: 4384124 bytes, checksum: ef38f7e72b8747c73ba1ab830eb12852 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-01-30T13:31:57Z (GMT) No. of bitstreams: 1 ValdemirPraxedesDaSilvaNeto_TESE.pdf: 4384124 bytes, checksum: ef38f7e72b8747c73ba1ab830eb12852 (MD5) / Made available in DSpace on 2017-01-30T13:31:57Z (GMT). No. of bitstreams: 1 ValdemirPraxedesDaSilvaNeto_TESE.pdf: 4384124 bytes, checksum: ef38f7e72b8747c73ba1ab830eb12852 (MD5) Previous issue date: 2016-04-29 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Os sistemas modernos de comunica??es demandam dispositivos com elevado desempenho de opera??o. Para o atendimento dessa demanda, torna-se essencial o desenvolvimento de novos dispositivos que sejam leves, de baixo custo, que apresentem facilidade de constru??o e capacidade de integra??o com outros circuitos que integram o sistema por completo. Desta forma, novas configura??es de circuitos integrados de micro-ondas atraem cada vez mais a aten??o dos pesquisadores, pelo bom desempenho na integra??o e prototipagem de sistemas de transmiss?o e recep??o de sinais sem fio. Este trabalho prop?e e detalha a aplica??o de uma t?cnica num?rica, constitu?da por uma formula??o de onda completa, baseada no conceito de ondas eletromagn?ticas e no princ?pio da reflex?o e transmiss?o de ondas na interface do circuito: Wave Concept Iterative Procedurte (WCIP). O m?todo Wave Concept Iterative Procedure (WCIP), ou m?todo iterativo das ondas ? apresentado como uma ferramenta com alto grau de precis?o no estudo de circuitos planares de micro-ondas. S?o propostas novas configura??es de estruturas de antenas, filtros e superf?cies seletivas de frequ?ncia. Para antenas, s?o apresentadas antenas com patch fractal aleat?rio, nas configura??es tradicionais e como monopolo. S?o realizadas an?lise da resposta em frequ?ncia dessas antenas impressas em diferentes substrato diel?tricos, dentre eles materiais t?xteis. Foram obtidos e discutidos resultados para frequ?ncia de resson?ncia, largura de banda, perda de retorno e diagrama de radia??o. Foram investigadas duas configura??es de filtros planares. Suas s?nteses e caracteriza??o da resposta em frequ?ncia foram apresentadas e realizadas por meio da aplica??o do m?todo WCIP. S?o mostrados os resultados para sua resposta em frequ?ncia. Nesta tese, s?o analisadas diferentes configura??es de FSS, tais como: FSS com elementos fractais, recongur?veis e FSS baseadas em arranjos n?o uniformes de elementos. Alguns prot?tipos dos dispositivos propostos foram constru?dos e os resultados experimentais comprovaram o modelo matem?tico apresentado. Os resultados obtidos tamb?m foram comparados com os resultados simulados pelo Ansoft HFSS, tendo sido observada uma boa concord?ncia entre eles. / The modern communications systems require devices with high operating performance. For the supply of this demand, it is essential to develop new devices that are lightweight, low cost, showing ease of construction and ability to integrate with other circuits that make up the system completely. Thus, new configurations of integrated microwave circuits increasingly attract the attention of researchers, the good performance in the integration and prototyping of transmitting and receiving wireless signals systems. This paper proposes and details the application of a numerical technique, consisting of a full-wave formulation, based on the concept of electromagnetic waves and the principle of reflection and wave transmission circuit in the interface: Wave Concept Iterative Procedure (WCIP). The method Wave Concept Iterative Procedure (WCIP) or waves iterative method is presented as a tool with high precision in planar circuits study microwave. New configurations are proposed antenna structures, filters, and frequency selective surfaces. For antennas, antennas are presented with random fractal patch in traditional settings and how monopole, response analysis are performed in frequency of such printed antennas in different dielectric substrate, including textiles. Results for resonance frequency, bandwidth, return loss and radiation pattern were obtained and discussed. Two planar filter settings were presented. Their synthesis and characterization of the frequency response were presented and carried out by applying the method WCIP. Results for its frequency response are shown. FSS different settings are presented in this thesis, such as: FSS with fractal elements, recongur?veis and FSS based on non-uniform arrangement of elements. Some prototypes of the devices proposed in this thesis were built and the experimental results showed the mathematical model presented. The results were also compared with the Ansoft HFSS simulation results, it was observed a good correlation between them. / 2019-06-21
59

Projeto de antenas multifuncionais integradas com superf?cies seletivas em frequ?ncia

Pinheiro, Bruno de Melo 04 July 2016 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-02-13T19:22:37Z No. of bitstreams: 1 BrunoDeMeloPinheiro_DISSERT.pdf: 2550891 bytes, checksum: 2b356848195a021792d535749a33c6de (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-02-14T17:30:41Z (GMT) No. of bitstreams: 1 BrunoDeMeloPinheiro_DISSERT.pdf: 2550891 bytes, checksum: 2b356848195a021792d535749a33c6de (MD5) / Made available in DSpace on 2017-02-14T17:30:41Z (GMT). No. of bitstreams: 1 BrunoDeMeloPinheiro_DISSERT.pdf: 2550891 bytes, checksum: 2b356848195a021792d535749a33c6de (MD5) Previous issue date: 2016-07-04 / Esse trabalho visa aplicar Superf?cies Seletivas em Frequ?ncia (FSS) em arranjos de antenas planares, propondo meios que tragam melhores resultados em termos de diretividade, ganho e largura de banda. Al?m desse estudo, tamb?m foi feito inicialmente um estudo das caracter?sticas de arranjos de antenas de microfita, acoplamento m?tuo entre elementos do arranjo, trucamento do plano de terra e seus poss?veis efeitos positivos nas caracter?sticas de radia??o da antena. Para realizar tal estudo, foram reproduzidos alguns estudos de antenas de microfita e arranjos de antena de microfita, com dois elementos tipo patch, onde foram feitos os estudos do truncamento diferenciado do plano de terra. Ap?s constatar o efeito desse estudo, foi feita a escolha dos par?metros ?timos para as caracter?sticas de radia??o da antena para que possam ser feitos testes com novas geometrias de FSS sobre a antena em estudo. Esse estudo foi realizado inicialmente por meio de simula??es com o aux?lio de softwares comerciais e em seguida foram constru?dos prot?tipos dos melhores resultados encontrados na simula??o, cujos resultados foram comparados com medi??es reais para comprovar sua utilidade em aplica??es reais. / This work aims to attribute the use of Frequency Selective Surfaces (FSS) together with planar antenna arrays, proposing ways to grant better results in terms of directivity, gain and bandwidth. In addition to that study it will also be made a study about the characteristics of the arrays of microstrip antennas, mutual coupling between the elements of the array, ground plane trunking, and its benefits for the for the radiation characteristics of the antenna. For the accomplishment of that study, some results for microstrip antennas and microstrip antenna arrays with two elements were reproduced, having the unusual ground plane trunking study in addition to that. As soon as its effects were verified, the optimal parameters for the radiation characteristics of the antenna were selected and applied, so the new geometry of FSS could start being proposed on that antenna. That initial study have been made with only simulations using a commercial software and this was followed by the fabrication of prototypes of the best results of the simulations. The prototypes were measured and their results were tested and verified to be useful for the real applications, by comparison with the simulated results.
60

Lentes de Microondas de bajo perfil en la banda de ondas milimétricas

Moy Li, Hon Ching 02 September 2020 (has links)
[ES] Los sistemas de antenas de bajo perfil en la banda de ondas milimétrica han suscitado un creciente interés en los últimos años. Esta tesis presenta el diseño de antenas de bajo perfil basadas en lentes planas de microondas de doble polarización, con alta ganancia y con simetría en el diagrama de radiación. En concreto, la tesis se enfoca en lentes planas con dieléctricos artificiales, e iluminadas por bocinas de bajo perfil. Para mejorar esta iluminación, también se han diseñado alimentadores de bajo perfil con dieléctricos artificiales. En esta Tesis se realiza una revisión de diferentes métodos para el control de la constante de propagación en celdas periódicas de superficies selectivas en frecuencia (FSS), así como de los parámetros más importantes que rigen su comportamiento electromagnético. Las FSS multicapa son idóneas para el diseño de lentes planas de microondas ya que permiten controlar la fase del coeficiente de transmisión con pocas pérdidas, y son fáciles de diseñar y construir. Las lentes diseñadas con este tipo de FSS son estructuras planas, de bajo perfil y peso reducido. Esto se debe a la capacidad de las FSS de modificar la constante de propagación por medio de una estructura que no requiere contacto entre capas. Para poder iluminar las lentes apropiadamente, en esta tesis se analizan diversos tipos de alimentadores y se propone un alimentador de bajo perfil con gran pureza de polarización y alta eficiencia. Esto se consigue insertando corrugaciones radiales en las paredes de la bocina, con lo que se consigue excitar un modo híbrido cuya distribución de campo es prácticamente uniforme en toda la apertura. Dado el coste computacional del análisis de onda completa de las lentes planas de microondas, en esta tesis se propone el diseño de las lentes usando gráficas paramétricas de las celdas unidad de las FSS. Estos diseños se han fabricado y medido, dando unos resultados experimentales excelentes, tanto en adaptación como en radiación. Estos resultados demuestran la viabilidad de usar FSS multicapa para el diseño de lentes planas de microondas. / [EN] Low-profile antenna systems in the millimeter-wave band have experienced an increasing interest in recent years. This thesis presents the design of low-profile antennas based on microwave flat lenses with double polarization, with high gain, and symmetric radiation pattern. In particular, the thesis focuses on flat lenses with artificial dielectrics, and illuminated by low-profile feeders. To improve this illumination, low-profile feeders with artificial dielectrics have also been designed. In this thesis, a review of different methods for the control of the propagation constant in periodic cells of frequency selective surfaces (FSS), as well as the most important parameters that govern its electromagnetic behavior, is carried out. The multilayer FSS are ideal for the design of flat microwave lenses since they allow controlling the phase of the transmission coefficient with few losses and are easy to design and build. Lenses designed with this type of FSS are flat structures, low profile, and low weight. This is due to the ability of the FSS to modify the propagation constant through a structure that does not require contact between layers. In order to be able to illuminate the lenses properly, in this thesis different types of feeders are analyzed and a low-profile feeder with high polarization purity, and high efficiency is proposed. This is achieved by inserting radial corrugations into the walls of the horn, which makes it possible to excite a hybrid mode whose field distribution is practically uniform throughout the aperture. Given the computational cost of the full-wave analysis of microwave flat lenses, this thesis proposes the design of the lenses using parametric studies of the FSS unit cells. These designs have been manufactured and measured, giving excellent experimental results, both in matching and radiation. These results demonstrate the feasibility of using multilayer FSS for the design of microwave flat lenses. / [CA] Els sistemes d'antenes de baix perfil en la banda d'ones millimètriqueses han suscitat un creixent interés en els últims anys. Aquesta tesi presenta el disseny d'antenes de baix perfil basades en lents planes de microones de doble polarització, amb alt guany i amb simetria en el diagrama de radiació. En concret, la tesi s'enfoca en lents planes amb dielèctrics arti- ficials, i il luminades per botzines de baix perfil. Per a millorar aquesta il luminació, també s'han dissenyat alimentadors de baix perfil amb die- lèctrics artificials. En aquesta Tesi es realitza una revisió de diferents mètodes per al control de la constant de propagació en cel les periòdiques de superfícies selectives en freqüència (FSS), així com dels paràmetres més importants que regeixen el seu comportament electromagnètic. Les FSS multicapa són idònies per al disseny de lents planes de microones perquè permeten controlar la fase del coeficient de transmissió amb poques pèrdues, i són fàcils de dissenyar i construir. Les lents dissenyades amb aquesta mena de FSS són estructures planes, de baix perfil i pes reduït. Això es deu a la capacitat de les FSS de modificar la constant de propagació per mitjà d'una estructura que no requereix contacte entre capes. Per a poder il luminar el lent apropiadament, en aquesta tesi s'analitzen di- versos tipus d'alimentadors i es proposa un alimentador de baix perfil amb gran puresa de polarització i alta eficiència. Això s'aconsegueix inserint co- rrugacions radials en les parets de la botzina, amb el que s'aconsegueix excitar una mode híbrid amb una distribució de camp pràcticament uni- forme en tota l'obertura. Donat el cost computacional de l'anàlisi d'ona completa de les lents planes de microones, en aquesta tesi es proposa el disseny de les lents usant gràfi- ques paramètriques de les cel les unitat de les FSS. Aquests dissenys s'han fabricat i mesurat, donant uns resultats experimentals excel lents, tant en adaptació com en radiació. Aquests resultats demostren la viabilitat d'usar FSS multicapa per al disseny de lents planes de microones. / Moy Li, HC. (2020). Lentes de Microondas de bajo perfil en la banda de ondas milimétricas [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/149563 / TESIS

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