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Previous issue date: 2014-09-25 / As superf?cies seletivas em frequ?ncia s?o estruturas cada vez mais comuns
em sistemas de telecomunica??es por apresentarem vantagens geom?tricas
e eletromagn?ticas. J? as superf?cies seletivas em frequ?ncia com
geometria do tipo fractal permitiram uma redu??o, ainda maior, no comprimento
el?trico proporcionando uma maior flexibilidade no projeto dessas
estruturas. Neste trabalho, ? investigado o uso das geometrias multifractais
nas superf?cies seletivas em frequ?ncia. Foram propostas e analisadas tr?s
estruturas com diferentes geometrias multifractais. A primeira estrutura
permitiu projetar estruturas multibanda com maior flexibilidade no controle
das frequ?ncias de resson?ncias e largura de banda. J? a segunda
estrutura proporcionou um aumento de largura de banda mesmo com o
aumento do n?vel fractal. A terceira estrutura apresentou resposta com estabilidade
angular, dupla polariza??o e permitiu um aumento de largura de
banda com o crescimento da mulfractalidade da estrutura. Al?m disso, as
estruturas propostas aumentaram o grau de liberdade nos projetos multibanda,
visto que possuem m?ltiplas propor??es de frequ?ncias de resson?ncias
entre as bandas adjacentes, e s?o f?ceis de ser implementadas. A
valida??o das estruturas propostas foi verificada, inicialmente, atrav?s de
simula??es realizadas no software Ansoft Designer e, em seguida, foram
constru?das as estruturas e obtidos os resultados experimentais / Frequency Selective surfaces are increasingly common structures in telecommunication
systems due to their geometric and electromagnetic advantages.
As a matter of fact, the frequency selective surfaces with fractal
geometry type would allow an even bigger reduction of the electrical
length which provided greater flexibility in the design of these structures.
In this work, we investigated the use of multifractal geometry in
frequency selective surfaces. Three structures with different multifractal
geometries have been proposed and analyzed. The first structure allowed
the design of multiband structures with greater flexibility in controlling
the resonant frequencies and bandwidth. The second structure provided a
bandwidth increase even with the rising of the fractal level. The third structure
showed response with angle stability, dual polarization and provided
room for a bandwidth increase with the rising of the structural multifractality.
Furthermore, the proposed structures increased the degree of freedom
in the multiband designs because they have multiple resonant frequencies
ratios between adjacent bands and are easy to deploy. The validation of
the proposed structures was initially verified through simulations in Ansoft
Designer software and then the structures were constructed and the
experimental results obtained
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/19570 |
| Date | 25 September 2014 |
| Creators | Braz, Erico Cadineli |
| Contributors | 79090095420, http://lattes.cnpq.br/1982228057731254, Gomes Neto, Alfredo, 33312079420, http://lattes.cnpq.br/1403715441701958, Fernandes, Humberto C?sar Chaves, 13097628487, http://lattes.cnpq.br/0246709532151067, Silva, Jos? Patroc?nio da, 67160042468, http://lattes.cnpq.br/5753289728835624, Mani?oba, Robson Hebraico Cipriano, 04991904404, http://lattes.cnpq.br/4396628695466189, Campos, Ant?nio Luiz Pereira de Siqueira |
| Publisher | Universidade Federal do Rio Grande do Norte, PROGRAMA DE P?S-GRADUA??O EM ENGENHARIA EL?TRICA E DE COMPUTA??O, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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