Linear Arrays
Mostrando 1-12 de 105 artigos, teses e dissertações.
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1. Series Fed Designs of Planar Circular and Hexagonal Microstrip Antenna Arrays for High Gain and Reduced First Side Lobe Level Radiation
Abstract To achieve a high gain and low first side-lobe level, variants of linear and planar series fed circular and hexagonal microstrip antenna arrays using the binomial distribution, are proposed around 3000 MHz frequency band, on thinner Arlon substrate (h ~ 0.027λg). The linear 7 × 1 array of circular patches, yields first side-lobe level of −25 dB
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2022
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2. Synthesis of Sparse Arrays Based On CIGA (Convex Improved Genetic Algorithm)
Abstract In this paper, a novel hybrid algorithm on beam pattern synthesis of sparse arrays is proposed, which aims at minimizing the peak sidelobe level (PSLL). Sparse arrays can provide higher spatial resolution and relatively lower sidelobe than general arrays, but it is necessary to solve the multi-constraint problem of nonconvex nonlinear. Thus, we prop
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2020-12
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3. Optimization of Planar Antenna Arrays Using the Firefly Algorithm
Abstract This paper describes the application of the Firefly Algorithm for the optimization of linear and planar antenna arrays. In order to demonstrate the potential of this technique, three applications are reported. The first one is the synthesis of a radiation pattern with isoflux distribution with a non-uniformly spaced linear array composed of isotropi
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2019-03
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4. Quantum Particle Swarm Optimization for Synthesis of Non-uniformly Spaced Linear Arrays with Broadband Frequency Invariant Pattern
Abstract This paper describes a method using Quantum Particle Swarm Optimization to obtain a broadband frequency invariant pattern for synthesis of nonuniformly spaced linear array of isotropic antennas. Two cases related to this work using QPSO have been studied, namely, in the first case, the generated frequency invariant far-field pattern is broadside in
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2017-09
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5. Design of Microstrip Antenna Array with Suppressed Back Lobe
Abstract A practical procedure to reduce the back lobe level of linear microstrip antenna arrays is presented in this paper. The novel concept consists in the design of the radiators asymmetrically positioned with respect to the ground plane. In order to validate this technique, a four-element linearly-polarized array is designed in the HFSS software and a p
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2017-04
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6. Ultrafast Dynamics of Au Nanopyramid Interfaces Prepared by Nanosphere Lithography: Effect of Substrate Chemical Composition
This work describes ultrafast spectroscopy studies of Au triangular pyramid particle arrays deposited over glass (termed Au/glass), and 190 nm indium tin oxide (ITO) film (termed Au/ITO/glass) prepared by nanosphere lithography. The linear absorption spectra of Au/glass and Au/ITO/glass exhibit surface plasmon resonances at 800 and 870 nm, respectively, in g
J. Braz. Chem. Soc.. Publicado em: 2016-02
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7. Whole transcriptome organisation in the dehydrated supraoptic nucleus
The supraoptic nucleus (SON) is part of the central osmotic circuitry that synthesises the hormone vasopressin (Avp) and transports it to terminals in the posterior lobe of the pituitary. Following osmotic stress such as dehydration, this tissue undergoes morphological, electrical and transcriptional changes to facilitate the appropriate regulation and relea
Braz J Med Biol Res. Publicado em: 02/12/2013
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8. Nulls and side lobe levels control in a time modulated linear antenna array by optimizing excitations and element locations using RGA
In this paper a novel approach based on the Real coded Genetic Algorithm (RGA) is proposed to improve nulling performance as well as suppression of Side Lobe Level (SLL) of a Time Modulated Linear Antenna Arrays (TMLA). RGA adjusts the static excitation amplitudes as well as the location of each element from the origin to place deeper nulls in the desired di
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2013-12
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9. Síntese e caracterização de nanoestruturas peptídicas: estudos espectroscópicos e aplicações / Synthesis and characterization of peptide nanostructures: spectroscopic studies and applications
The study had as aimed the development of nanostructured materials based on processes of molecular self-assembly of peptide compounds in order to obtain systems of great structural versatility seeking possible applications related to bionanotechnology. In this regard, peptide sequences based on linear and cyclic precursors were synthesized by solid-phase met
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 27/02/2012
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10. Processamento largamente linear em arranjo de antenas : proposta, avaliação e implementação prática de algoritmos / Widely linear processing in antenna arrays : proposal, evaluation and practical implementation of algorithms
O Processamento Largamente Linear, desenvolvido durante a década de 1990, tem levado a uma melhoria no desempenho de algoritmos adaptativos para determinadas situações que empregam sinais impróprios. Quando aplicado a arranjos de antenas, esse tipo de processamento apresenta a potencialidade ser mais robusto e eficiente que as técnicas clássicas de fil
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 11/02/2011
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11. Antenas de microfita com patch supercondutor a 212 K
This work has as main objective to study the application of microstrip antennas with patch and use of superconducting arrays of planar and linear phase. Was presented a study of the main theories that explain clearly the superconductivity. The BCS theory, Equations of London and the Two Fluid Model are theories that supported the implementation of the superc
Publicado em: 2010
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12. Aplicações de arranjos de antenas de microfita com patch supercondutor
This work has as main objective the study of arrays of microstrip antennas with superconductor rectangular patch. The phases and the radiation patterns are analyzed. A study of the main theories is presented that explain the microscopic and macroscopic phenomena of superconductivity. The BCS, London equations and the Two Fluid Model, are theories used in the
Publicado em: 2010