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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

Desenvolvimento de FSS mecanicamente reconfigur?vel para aplica??es em micro-ondas

Carvalho, Rafaela Gomes Gon?alves de 30 January 2017 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-07-03T12:46:24Z No. of bitstreams: 1 RafaelaGomesGoncalvesDeCarvalho_DISSERT.pdf: 3495415 bytes, checksum: 8f2ba59f5497dd2972e751f7feaa758f (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-07-06T15:18:49Z (GMT) No. of bitstreams: 1 RafaelaGomesGoncalvesDeCarvalho_DISSERT.pdf: 3495415 bytes, checksum: 8f2ba59f5497dd2972e751f7feaa758f (MD5) / Made available in DSpace on 2017-07-06T15:18:49Z (GMT). No. of bitstreams: 1 RafaelaGomesGoncalvesDeCarvalho_DISSERT.pdf: 3495415 bytes, checksum: 8f2ba59f5497dd2972e751f7feaa758f (MD5) Previous issue date: 2017-01-30 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / A reconfigurabilidade ? uma caracter?stica muito importante nos sistemas modernos de comunica??o, pois permite que uma mesma estrutura se adapte aos diferentes cen?rios de uma mesma aplica??o, como por exemplo, radomes, r?dio cognitivo, e telas adaptativas que bloqueiam transmiss?es sem fio indesejadas. Essa caracter?stica pode ser alcan?ada mediante m?todos tradicionais, como o uso de dispositivos semicondutores ativos (diodos PIN, Schottky) ou capacitores vari?veis acoplados a cada elemento b?sico da superf?cie seletiva de frequ?ncia (FSS), sendo necess?rio o uso de um circuito separado para alimentar esses dispositivos. No entanto, estes m?todos requerem um n?mero elevado de elementos ativos, o que aumenta a complexidade e o custo de fabrica??o, abrindo espa?o para o surgimento de t?cnicas mais simples e robustas quanto ? seletividade, como a reconfigurabilidade mec?nica. Este trabalho consiste no desenvolvimento de uma superf?cie seletiva de frequ?ncia (FSS) reconfigur?vel, para operar na banda X, formada por patches condutores triangulares impressos em uma camada de diel?trico de fibra de vidro (FR-4). A FSS desenvolvida permite a reconfigura??o da frequ?ncia de resson?ncia a partir da varia??o do ?ngulo da onda incidente na estrutura, com polariza??o TE, e pode ser aplicada em sistemas de comunica??o via sat?lite a partir de uma interface microcontrolada. A an?lise da estrutura da FSS ? efetuada atrav?s do software Ansoft Designer do M?todo das Ondas ? WCIP. / Reconfigurability is a very important feature in modern communication systems because it allows the same structure to adapt to different scenarios of the same application, such as radomes, cognitive radio, and adaptive screens that block unwanted wireless transmissions. This characteristic can be achieved by traditional methods, such as the use of active semiconductor devices (PIN and Schottky diodes) or variable capacitors coupled to each basic element of the frequency selective surface (FSS), requiring the use of a separate circuit to feed these components. However, these methods require a high number of active elements, which increases the complexity and cost of manufacturing, opening space for the emergence of simpler and more robust techniques for selectivity, such as mechanical reconfigurability. This work consists of the development of a reconfigurable frequency selective surface (FSS), to operate in the X-band, composed of triangular patch elements printed on a dielectric layer of fiberglass (FR-4). The developed FSS allows the reconfiguration of the resonant frequency from the variation of the angle of the incident wave in the structure, in the TE polarization, and can be applied in satellite communication systems through a microcontrolled interface. The analysis of the structure of the FSS is done through Ansoft Designer software and WCIP method.

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