Navegando por Assunto "Nanoantena"

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Acesso aberto (Open Access)
Análise comparativa de nanoantenas plasmônicas no modo de recepção para a aplicação em nanocircuito óptico.
(Universidade Federal do Pará, 2020-01-30) LOPES, Patrik Coelho; COSTA, Karlo Queiroz da; http://lattes.cnpq.br/7932708321834647; https://orcid.org/0000-0003-4393-3217
In this work, a theoretical study is made for different cases of optical nanoantennas. Numerical analyzes are performed using the Finite Element Method (FEM). The first part of the analysis will be done with the isolated nanoantennas considered: dipole,dipole-loop, loop and rod-loop. Initially it is made for the transmission mode to obtain important parameters for the study of nanoantennas, such as input impedance, reflection coefficient, radiation efficiency and gain diagram. Later in reception mode, excited by a plane wave linearly polarized, varying the direction of polarization. Where the power received by charge versus frequency and the near-field electric are investigated for antennas. The results show that the case of the dipole-loop nanoantenna is the most efficient (reaching up to and er = 81.25%) in addition to a better reception band. The second part is presented the application of an optical nanocircuit, composed of the receiving loop connected to a bifilar Optical Transmission Line (OTL) with a dipole at the line end. Also investigated are the near-field and the received power for the nanocircuits analyzed separately, with a load at the terminal of the streaming. Finally, the excitation of the nanocircuit is done through an opening probe modeled by a gaussian beam, focused on the receiving loop, transferring energy to the emitting dipole, with a standing wave pattern, the electromagnetic coupling of the nanocircuit turns with the Gaussian beam, showed better results (with a maximum reached of PZC = −103 dBm) compared to the plane wave (with value maximum of PZC = −125 dBm), with the power received at the load of ZC = 50Ω.
Acesso aberto (Open Access)
Análise de nanoenlaces ópticos sem fio compostos por nanoantenas plasmônicas yagi-uda e dipolo
(Universidade Federal do Pará, 2019-12-17) GARCIA, Tiago dos Santos; COSTA, Karlo Queiroz da; http://lattes.cnpq.br/7932708321834647
This work shows a comparative theoretical analysis of plasmonic nanoantennas Yagi-Uda and dipole wireless optical nanolinks. All results found from the isolated antennas at transmission mode such as, input impedance, directivity, gain, radiation efficiency, reflection coeficiente and radiation diagram were obtained by the linear Method of Moments, assitionally, the effect of a silicon dioxide substract on antenna resonant properties were obtained by the Finite Element Method through COMSOL Multiphysics software. The numerical analysis of the nanolink is performed by the linear Method of Moments, witch the transmission power and the near electric field are investigated and optimized for the nanolinks Yagi-Uda/Yagi-Uda, Yagi-Uda/dipole and dipole/dipole. The results show that the Yagi-Uda/Yagi-Uda nanolinks offers an improvement in power transmission at some frequency points over the nanolinks dipole/dipole and Yagi-Uda/dipole. In addition, the results demonstrate that all three links can operate at good transmit power at different frequency points, varying the load impedance of the receiving antenna.
Acesso aberto (Open Access)
Otimização de nanoantenas plasmônicas para células solares orgânicas
(Universidade Federal do Pará, 2016-01-18) SILVA JÚNIOR, Marcelino Lopes Corrêa da; DMITRIEV, Victor Alexandrovich; http://lattes.cnpq.br/0684541646225359; COSTA, Karlo Queiroz da; http://lattes.cnpq.br/7932708321834647
This work shows a theoretical nanoantennas study about organic solar cells of thin films, occasioning the increase in the efficiency of light absorption. The unitary organic solar cell formed by a reflector silver block, an active layer formed by the semiconductor P3HT:PCBM and a nanoantenna, also made of silver. The numerical analysis of the device is made through the Finite Element Method; the materials are analysed from the relative permittivity. Firstly, we executed the validation of the nanostructure through the numerical method. Then, we apply the geometric optimization process in the other nanoantenna models. This optimization process was based on nanoantennas geometrical parameters preserving its superficial area. Since were considered four new models of nanoantennas with different geometrical parameters, which means, conical nanoantennas, root cone, and exponential root cone 1 and 2. It was observed, from the efficiency of integrated absorption for different incidence angles and light polarization, current density and plasmonic decay that the nanoantennas, the root cone and the exponential cone 2, gave better performance compared to the other models.