Projeto de mantos metamateriais para redução de espalhamento eletromagnético na faixa de micro-ondas

• Ano de defesa: 2016
• Autor(a) principal: Fábio Júlio Fonseca Gonçalves
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais
• Palavras-chave em Português: Ondas eletromagneticas Espalhamento; Engenharia elétrica; Metamateriais; Otimização multiobjetivo
• Link de acesso: https://hdl.handle.net/1843/RAOA-BC9HXW

The design of electromagnetic cloaks fundamentally involves the determination of their materials. In this context, the coordinate transformation technique is flexible to be applied in different geometries. However, the resulting material is challenging even for metamaterials, since it is non-homogeneous, anisotropic and singular. In fact, invisibility and simplicity in materials are conflicting attributes. In arbitrary geometries, the problem becomes even more complex. This thesis considers different cloak models and aims to adjust their characteristics to provide a better performance. The first studied models have all-dielectric layers and contributions on the enlargement of the bandwidth were achieved by a multi-objective optimization. Because of the limitations in the dielectric cloaks in terms of performance and geometry, the numerical mapping provided by Laplace's equation becomes interesting to generate the materials for an arbitrary cloak. Thus, in order to obtain a satisfactory performance with simpler cloaks, here the optimization of the out-of-plane transformation is performed, since it can control the cloak materials for any geometry. This thesis also contributes with the study of small area mappings, with further optimization in the discretized materials. Cloaks with different geometries and levels of complexity were used for the development of this thesis.