Made available in DSpace on 2014-12-17T14:56:05Z (GMT). No. of bitstreams: 1 KesiaCS.pdf: 532004 bytes, checksum: e5e91d569fd4794eb815f8bbbd565c37 (MD5) Previous issue date: 2005-12-20 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Recently the planar antennas have been studied due to their characteristics as well as the advantages that they offers when compared with another types of antennas. In the mobile communications area, the need for this kind of antennas have became each time bigger due to the intense increase of the mobile communications that needs of antennas which operate in multifrequency and wide bandwidth. The microstrip antennas presents narrow bandwidth due the loss in the dielectric generated by radiation. Another limitation is the radiation pattern degradation due the generation of surface waves in the substrate. In this work some used techniques to minimize the disadvantages (previously mentioned) of the use of microstrip antennas are presented, those are: substrates with PBG material - Photonic Bandgap, multilayer antennas and with stacked patches. The developed analysis in this work used the TTL - Transverse Transmission Line method in the domain of Fourier transform, that uses a component of propagation in the y direction (transverse to the direction real of propagation z), treating the general equations of electric and magnetic field as functions of y and y . This work has as objective the application of the TTL method to microstrip structures with single and multilayers of rectangular and triangular patches, to obtaining the resonance frequency and radiation pattern of each structure. This method is applied for the treatment of the fields in stacked structures. The Homogenization theory will be applied to obtaining the effective permittivity for s and p polarizations of the substrate composed of PBG material. Numerical results for the triangular and rectangular antennas with single layer, multilayers resonators with triangular and rectangular patches are presented (in photonic and isotropic substrates). Conclusions and suggestions for continuity of this work are presented / Recentemente as antenas planares t?m despertado interesses devido ?s suas caracter?sticas assim como pelas vantagens que oferecem quando comparadas com os demais tipos de antenas. Na ?rea de comunica??es m?veis a necessidade de antenas desse tipo tem se tornado cada vez maior devido ao intenso crescimento das comunica??es m?veis que necessitam de antenas que operem em multifreq??ncia e em banda larga. As antenas de microfita apresentam largura de banda estreita devido ?s perdas no diel?trico geradas pela irradia??o. Outra limita??o ? a degrada??o do diagrama de irradia??o devido ? gera??o de ondas de superf?cie no substrato. Neste trabalho s?o apresentadas algumas t?cnicas usadas para tentar minimizar as desvantagens (citadas acima) do uso de antenas de microfita, sendo elas: substratos com material PBG – Photonic Bandgap, antenas em multicamadas e com patches empilhados. As an?lises desenvolvidas neste trabalho foram realizadas com a utiliza??o do m?todo LTT – Linha de Transmiss?o Transversa no dom?nio da transformada de Fourier que utiliza uma componente de propaga??o na dire??o y (transversa ? dire??o real de propaga??o z), tratando assim as equa??es gerais dos campos el?tricos e magn?ticos em fun??es de y e y . Este trabalho tem como objetivo a aplica??o do m?todo LTT ?s estruturas de microfita com uma e multicamadas de patch retangular e triangular, para a obten??o da freq??ncia de resson?ncia e diagrama de irradia??o de cada estrutura. Este m?todo ? aplicado para o tratamento dos campos em estruturas planares empilhadas. A teoria da Homogeneiza??o ser? aplicada para a obten??o da permissividade efetiva para as polariza??es s e p dos substratos compostos de material PBG - Photonic Bandgap. Resultados num?ricos para as antenas triangulares e retangulares com uma camada e ressoadores com multicamadas de patch retangular e triangular s?o apresentados (em substratos isotr?picos e fot?nicos). S?o apresentadas conclus?es e sugest?es para a continuidade deste trabalho