Fractal Geometry
Mostrando 1-12 de 34 artigos, teses e dissertações.
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1. Synthesis and Mechanical Reconfiguration of Ground Plane Tilted Microstrip Antennas Based on Tetra-Circle Fractals
Abstract A synthesis procedure of a mechanically reconfigurable antenna based on tetra-circle fractal patch elements is presented, enabling to change both resonant frequencies and radiation pattern performance. The antenna geometry reconfiguration is implemented by tilting the ground plane of the microstrip antenna with respect to the fractal patch and subst
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2020-06
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2. Dimensionalidade fractal e invariância de escala em circuitos elétricos AC e linhas de transmissão
Resumo A geometria fractal fascina pela capacidade de descrever formas geométricas complexas e que usualmente estão presentes no mundo real . A dimensão fractal ou de Hausdorff d é utilizada para descrever leis de invariância de escala, em que as funções autossimilares seguem uma lei da forma f ( s x ) = s d f ( x ), sendo s o fator de escala. Intim
Rev. Bras. Ensino Fís.. Publicado em: 10/01/2020
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3. A Novel Fractal Multi-band Frequency Selective Surface
Abstract In this paper, a new multiband fractal frequency selective surface (MF-FSS) is proposed. The work presents a new fractal design methodology for FSSs with Swastika fractal patch elements. The proposed MF-FSS includes periodic arrays of metallic patches, printed on a single layer substrate. The structure parametric analysis is carried out in terms of
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 19/06/2019
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4. Using rodogram function to characterize hurst coefficient in rock profiles
Abstract Roughness is a fundamental feature to define rock deformability and resistance. A detailed characterization of discontinuity surface geometry is essential for understanding some of the rock’s mechanical behaviors. Fractal geometry has been used by several authors to correlate parameters such as the Hurst coefficient for JRC (Joint Roughness coeffi
REM, Int. Eng. J.. Publicado em: 2018-07
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5. Multiband FSS with Fractal Characteristic Based on Jerusalem Cross Geometry
Abstract This paper proposes a new Frequency Selective Surface (FSS) with modifications on the Jerusalem Cross (JC) geometry to provide a multiband response. Fractal levels are created by introducing concentric self-similar JC copies in the original unit cell. This modification results in new dipoles at the structure which allows for the appearance of new ba
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2017-12
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6. An Investigation on Morphology and Fractal Dimension of Diesel and Diesel-Biodiesel Soot Agglomerates
In this study, it is reported the fractal dimension and morphology of ultrafine particles emitted by a diesel engine run with B4, B50, and B100. Transmission electron micrographs evidenced two main groups of particles with characteristic and distinct morphological behaviors: (i) particle agglomerate structures self-organized within a fractal-like geometry, a
J. Braz. Chem. Soc.. Publicado em: 2017-08
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7. Multiband frequency selective surfaces with a modified multifractal cantor geometry
Self-affine property of a modified multifractal Cantor geometry is exploited to design frequency selective surfaces (FSS) with multiband response. The main advantage of the proposed structure is to design multiband FSS with multiple frequency ratios between the adjacent bands and easily-built structures. In addition, the proposed structure increases the degr
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2014-12
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8. Study of different shape Electromagnetic Band Gap (EBG) structures for single and dual band applications
In this paper, single and dual band EBG structures for wider bandwidth are proposed. In each of the discussed EBGs, a metallic patch of regular geometry is chosen for the unit element. The patch is further modified by cutting slots to get extra inductance and capacitance which results into lower cut-off frequency and larger bandwidth. The proposed EBG struct
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2014-06
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9. Electrical percolation, morphological and dispersion properties of MWCNT/PMMA nanocomposites
Nanocomposites of poly (methyl methacrylate) (PMMA) and carbon nanotubes have a high potential for applications where conductivity and low specific weight are required. This piece of work concerns investigations of the level of dispersion and morphology on the electrical properties of in situ polymerized nanocomposites in different concentrations of multi-wa
Mat. Res.. Publicado em: 09/05/2014
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10. On the design of nano-arm fractal antenna for UWB wireless applications
This paper presents the design of a nano-arm fractal antenna suitable for ultra wide band applications. The CPW-feed and fractal concept have been used to achieve the ultra wide bandwidth. The shape of the fractal geometry, the number of iterations and the number of nano-arms are the deciding factors for achieving wider impedance bandwidth. The experimental
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2013-06
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11. Estudo do efeito de substratos metamateriais em parâmetros de antenas de microfita
As antenas de microfita são objeto de estudo em diversos campos de pesquisa devido a suas inúmeras vantagens. A obtenção, em 1999, de uma nova classe de materiais, chamados metamateriais - normalmente compostos por elementos metálicos imersos em um meio dielétrico, tem atraído a atenção da comunidade científica, graças às suas propriedades eletro
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 03/02/2012
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12. Arranjos Log-Periódicos Compactos em Microfita com Elementos Fractais de Koch / Arranjos Log-Periódicos Compactos em Microfita com Elementos Fractais de Koch
This work aims to present how the application of fractal geometry to the elements of a log-periodic array can become a good alternative when one wants to reduce the size of the array. Two types of log-periodic arrays were proposed: one with fed by microstrip line and other fed by electromagnetic coupling. To the elements of these arrays were applied fractal
Publicado em: 2010