Negative Permittivity
Mostrando 1-8 de 8 artigos, teses e dissertações.
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1. Radially Periodic Metasurface Lenses for Magnetic Field Collimation in Resonant Wireless Power Transfer Applications
Abstract In this paper, a new procedure and topology of magnetic metasurface lens are proposed for improving the performance of Resonant Wireless Power Transfer systems. Firstly, three subwave-length unit cells are optimized in order to get negative magnetic permeability in the same frequency, each one with a different refractive index, and they are experime
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2022
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2. A High Gain Super Wideband Metamaterial Based Antenna
Abstract The paper proposes a high gain, metamaterial based super wideband (SWB) antenna. The SWB antenna has two inverted U slots which are responsible for two notches at 3.5 GHz and 5.5 GHz frequencies. A flower-shaped slot is etched from the radiator to obtain the SWB characteristics. The super wideband antenna has dimensions of 30×35 ×1.5 mm3 with FR4
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2021-06
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3. Effect of Metamaterial Cells Array on a Microstrip Patch Antenna Design
Abstract In this paper, a microstrip patch antenna (MPA) design was developed to verify the performance of a metamaterial cell array (MTM) Capacitive Loaded Loop (CLL) immersed in the substrate. The metamaterial was obtained from metal laminates designed inside a dielectric material, with dimensions carefully calculated to have the effective negative permitt
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2020-09
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4. A High Gain and Directivity Bow Tie Antenna Based on Single-Negative Metamaterial
Abstract This paper presents an antenna loaded with metamaterial to enhance its gain and directivity to improve the performance of a ground-penetrating radar system (GPR). We adjusted the parameters of the antenna to change its equivalent capacitance and inductance and applied an operating frequency of 0.5 GHz-1.2 GHz to create an ultra-wideband antenna. On
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2018-06
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5. Aplicação de novos materiais em transistores de efeito de campo ferroelétricos
In this work, we investigated the electrical properties of the polyelectrolyte PSS in its sodium form (PSS-Na, Polystyrene sulfonic in the sodium form) and acid form (PSS-H, polystyrene sulfonic in the acid form) and also doped with Fe3+ for application in Ferroelectric Field Effect Transistors (Fe-FET). The PSS-Na was acquired from Aldrich and PSS-H was obt
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 27/07/2012
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6. Metamaterial inspired improved antennas and circuits
Metamaterials exhibiting negative refraction have attracted a great amount of attention in recent years mostly due to their exquisite electromagnetic properties. These materials are artificial structures that exhibit characteristics not found in nature. It is possible to obtain a metamaterial by combining artificial structures periodically. We investigated t
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 06/12/2010
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7. Experimental methodology to development of metamaterial grids with near-zero and negative permittivity / Metodologia experimental de desenvolvimento de grades metamateriais com permissividade quase-zero e negativa
Metamateriais são estruturas ou arranjos geométricos feitos a partir de materiais comuns, dielétricos, condutores, magnéticos ou por combinação destes. Os metamateriais caracterizam-se principalmente por apresentarem propriedades especiais de permissividade ( e) e permeabilidade ( µ) não encontradas nos materiais em estado natural, cujo principal efe
Publicado em: 2009
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8. Aplicação da técnica LOD em métodos no domínio do tempo e freqüência para modelagem de meios convencionais e metamateriais / Application of LOD technique in time and frequency domain methods for modelling conventional and metamaterial media
This work focuses on developing efficient numerical methods, both in time and frequency domains, for modeling wave propagation in structures that present conventional media and/or metamaterial media combinations, particularly the metamaterials where both permeability and permittivity are simultaneously negative. In some cases, the simulation of such structur
Publicado em: 2007