Programa de Pós-Graduação em Engenharia Elétrica e de Computação - PPGEEC/UNICAMP
URI Permanente desta comunidadehttps://repositorio.ufpa.br/handle/2011/9606
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Navegando Programa de Pós-Graduação em Engenharia Elétrica e de Computação - PPGEEC/UNICAMP por Orientadores "GIAROLA, Attilio José"
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Item Acesso aberto (Open Access) Método das Diferenças Finitas no Domínio do Tempo (FDTD) aplicado a guias dielétricos controlados por plasma(Universidade Estadual de Campinas, 1996-02-09) FARIAS, Rubem Gonçalves; GIAROLA, Attilio José; http://lattes.cnpq.br/7834721061998959A finite-difference in the time domain (FDTD) formulation is developed for plasmas magnetized along an arbitrary direction and applicable to two dimensions (2D-FDTD) and to three dimensions (3D-FDTD) dielectric devices. Emphasis is given to the iterative calculation of the convolution between the electric field vector and the electric susceptibility tensor of the magnetized plasma. Various types of devices are also proposed for the propagation of signals in the millimeter-wave band. The method is applied to structures controlled by plasma. This plasma may be induced by an optical beam applied to a semiconductor layer deposited on the waveguide. In this case, the propagation characteristic of the waveguide is controlled by an optical beam with appropiate energy. This plasma may also also be introduced in the semiconductor by means of doping. For these devices the waveguide core is completely filled with plasma. With this option the propagation of the RF fields is controlled by a static magnetic field. Some devices with single and coupled waveguides are analyzed. The possibility of an effective control of phase and coupling, as well as the operating bandwidth with a single mode was examined, particularly with optically controlled waveguides. Due to the lack of data in the specialized literature, gradual discretization criteria and rigorous tests of convergence are proposed. Various types of data are used to accomplish this objective. As a result, a kind of discretization profile is obtained and is applied to the remaining devices.Item Acesso aberto (Open Access) Método rigoroso das diferenças finitas em análise de estruturas de guias dielétricos anisotrópicos com perfil de índice de refração variável(Universidade Estadual de Campinas, 1992-07-13) SOUZA SOBRINHO, Carlos Leônidas da Silva; GIAROLA, Attilio José; http://lattes.cnpq.br/7834721061998959A rigorous, general and versatil finite-difference formulation for the analysis of the propagation characteristics in structures, having the dielectric waveguide as the basic element, is presented here. In this formulation, the finite-diff erence method is used in the numerical solution of the scalar wave equation, written in terms of the transverse components of the magnetic field. As a result, a conventional eigenvalue problem is obtained without the presence of spurious modes (present in previous formulations), due to the implicit inclusion of the divergence of the magnetic field equal to zero. The general case of biaxial anisotropic dielectrics is considered, with the refractive index profile varying arbitrarily in the waveguide cross section. Dispersion characteristics for isolated and parallel coupled dielectric waveguides are calculated. The theoretical development was then used to solve particular problems and the results agree with those available from other methods. Results were obtained for a variety of guiding wave structures, of much interest, particularly for the development of integrated optics.Item Acesso aberto (Open Access) Propagação de ondas eletromagnéticas em meios com camadas múltiplas usando funções de Green diádicas e sua aplicação no modelamento de florestas(Universidade Estadual de Campinas, 1982) CAVALCANTE, Gervásio Protásio dos Santos; ROGERS, David Antony; GIAROLA, Attilio José; http://lattes.cnpq.br/7834721061998959