Wide Band Measurements
Mostrando 1-12 de 20 artigos, teses e dissertações.
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1. Omni-Directional Wideband Antenna Array with Solar Cells
Abstract Distributed sensor networks are becoming more and more widespread due to their substantial benefits to our daily lives. These sensors, in most cases, are distributed in nature and even may require mobility. This, in turn, implies omnidirectional collector units to collect the data from various sensors at arbitrary directions. This work summarizes th
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2021-03
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2. Double Layer Frequency Selective Surface for Ultra Wide Band Applications with Angular Stability and Polarization Independence
Abstract In this paper, a double layer stopband Frequency Selective Surface (FSS) for Ultra-Wide Band (UWB) applications is presented. The proposed FSS consists of two cascaded conventional FSS, one with double square loops and other with square loops. The − 10dB frequency band from 3.00 GHz to 11.64 GHz is achieved, with a fractional bandwidth of 149 %. E
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 12/09/2019
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3. Comparison between OFDM and STDCC mobile channel sounders at 3.5 GHz
In this paper, we present a comparison between OFDM and STDCC sounding techniques used to wide band channel characterization in suburban environments at 3.5 GHz band. Measurements of the received signal's power delay profile and power level for each of the sounding techniques were obtained. These experimental results are presented and compared. For this comp
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2013-06
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4. Propriedades ópticas, magnéticas e estruturais de monocristais Cs2NaAlF6 dopados com cromo trivalente / Optical, magnetic and structural properties of Cs2NaAlF6 single crystals doped with trivalent chromium
This work is devoted to study the optical, magnetic and structural properties of the elpasolite crystal Cs2NaAlF6 with 0.1, 1.0, 3.0, 10.0, 30.0 and 50.0% of Cr3+ ions. The interest on this material lies on the fact that such system presents a broad, intense band in the visible and infrared regions at room temperature and therefore can be used as a tunable r
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 09/08/2011
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5. ESTUDO DAS PROPRIEDADES ELETROLUMINESCENTES DE NOVOS COMPLEXOS TETRAKIS BETA-DICETONATOS DE EURÓPIO UTILIZADOS EM OLEDS / INVESTIGATION ON ELECTROLUMINESCENT PROPERTIES OF NOVEL TETRAKIS BETA-DIKETONATE COMPLEXES USED IN OLEDS
Rare-earth complexes present extremely sharp line emission making possible to use them in organic light-emitting devices (OLEDs) technology. This dissertation reports the study of three europium tetrakis beta-diketonate complexes: Li[Eu(dbm)(4)].(4)H(2)O, TMPip[Eu(dbm)(4)] and Morf[Eu(dbm)(4)]. UV-Vis absorption, photoluminescence (PL) and cyclic voltammetry
Publicado em: 2010
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6. Ordem-desordem: uma avaliação estrutural do Ba(ZrxTi1-x)O3 / Order-disorder: an evaluation structural of Ba(ZrxTi1x)O3
This work have as aim, the synthesis of ceramic powders of Ba(ZrxTi1x)O3 (x = 0, 0.25, 0.50, 0.75 and 1) by the polymeric precursor method and investigate the degree of structural order-disorder of these systems by different characterization techniques, such as: thermogravimetric analysis (TA), differential thermal analysis (DTA), X-ray diffraction (XRD), Ra
Publicado em: 2009
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7. Estudo da morfologia e dinâmica molecular de filmes de MEH-PPV via espalhamento de raios-x de alto ângulo e ressonância magnética nuclear do estado sólido / Morphology and molecular dynamics of MEH-PPV films using wide-angle x-ray scattering and solid-state nuclear magnetic resonance
The morphology and dynamic of MEH-PPV films prepared by casting from toluene and chloroform were studied using Wide-Angle X-ray Scattering (WAXS) and Solid-State Nuclear Magnetic Resonance (NMR) techniques, respectively. Evidences of the increase in the aggregation were obtained by WAXS, which revealed a tendency of increasing in the molecular ordering upon
Publicado em: 2007
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8. Development of wideband bandpass filter with zeros transmition for ultrawideband communication systems / Desenvolvimento de filtro passa-faixa banda larga com zeros de transmissão para sistemas de comunicação Ultra-Wideband (UWB)
The quick development of wireless communications has introduced new requirements for communications systems being the use of more selective microwave filters. Different filter structures have been developed for applications in UWB systems (Ultra WideBand). It is presented in [1, 2] the highly selective microstrip bandpass filter. In this work, a bandpass fil
Publicado em: 2007
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9. Correlated electron-hole transitions in bulk GaAs and GaAs-(Ga,Al)As quantum wells: effects of applied electric and in-plane magnetic fields
The effects of crossed electric and magnetic fields on the electronic and exciton properties in semiconductor heterostructures have been investigated within the effective-mass and parabolic band approximations for both bulk GaAs and GaAs-Ga1-xAl xAs quantum wells. The combined effects on the heterostructure properties of the applied crossed electric/magnetic
Brazilian Journal of Physics. Publicado em: 2006-09
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10. Um Estudo sobre Amplificadores de RF Faixa Larga / A wide band RF amplifiers study
The design of wide band RF amplifiers for CATV networks and wide band data networks, which achieve the specifications needed to handle hundreds of analogic and digital channels, must to be carry out, not only with computers but also with detailed modeling of all components. First, we started choosing a configuration that could provide the best distortion red
Publicado em: 2006
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11. Um Estudo sobre Amplificadores de RF Faixa Larga
The design of wide band RF amplifiers for CATV networks and wide band data networks, which achieve the specifications needed to handle hundreds of analogic and digital channels, must to be carry out, not only with computers but also with detailed modeling of all components. First, we started choosing a configuration that could provide the best distortion red
Publicado em: 2006
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12. Optical properties of K2LiAlF6:Cr3+ / Propriedades ópticas do K2LiAlF6:Cr3+
The interest in the study of insulating materials doped with transition metals arises from the fact that these systems present wide emission bands in the visible and near infrared regions, which turns them especially attractive as active media for tunable radiation. In this work we will present photoluminescence, absorption and excitation measurements at roo
Publicado em: 2006