Fdtd
Mostrando 1-12 de 53 artigos, teses e dissertações.
-
1. A Finite-Difference Time-Domain Formulation for Modeling Air Ionization Breakdown Streamers
Abstract A numerical model based on the finite-difference time-domain (FDTD) method is developed for calculating discharge currents and fields produced due air ionization between two electrodes. Electric conductivity σ of the ionized channel between two electrodes is calculated using non-linear equations, i.e., σ is obtained using functions of time. The fu
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2022
-
2. Semi-analytical Equations for Designing Terahertz Graphene Dipole Antennas on Glass Substrate
Abstract Semi-analytical equations are developed for aiding the process of designing terahertz graphene-based rectangular dipole antennas lying on glass substrates. It directly provides the dipole length required for obtaining resonance at a desired frequency since antenna width and graphene chemical potential are known. By using the finite-difference time-d
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2022
-
3. Lightning Protection Design for Small Riverboats Using the FDTD Method
Abstract The Amazon region has high lightning occurrence rates, with many lightning hot spots. Different rivers cross the Amazon rainforests and the people that live there use these rivers as roads to go from one place to another. Every year, lightning deaths are reported in the Brazilian Amazon region. In 2018, a lightning discharge struck a small riverboat
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2021-06
-
4. Smart Graphene-Based Frequency Selective Surface Designed to Act as Single or Dual Band Device with Reconfigurable Operation Bands
Abstract In this paper, a finite-difference time-domain (FDTD) formulation, based on the exponential matrix and on thin material sheet methods is developed for modeling subcellular thin graphene sheets. This formulation is validated by reproducing graphene frequency selective surfaces (FSS) known from literature. Then, we propose in this work a smart graphen
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 11/11/2019
-
5. Indoor Characterization of Power Delay Profile Using Equivalent Antenna Representation in Uniform FDTD Lattices
Abstract It is shown that proper representation of transmitting and receiving antennas in indoor environments are decisive for accurate prediction of electromagnetic power transfer parameters using the standard 3D-FDTD method. With the standard Yee method, it is not always possible to precisely describe all the geometrical details of electrically small anten
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2017-03
-
6. Computational Modeling of Geoelectrical Soundings using PML-FDTD
Abstract The Finite-Difference Time-Domain (FDTD) method was applied in order to analyze the transient responses of geoelectrical soundings that use circular electric dipole (CED) as source over stratified formations. The model was developed in cylindrical coordinates and a perfectly matched layer (PML) was incorporated to the domain to absorb wave reflectio
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2017-03
-
7. Spectral Method for Localization of Multiple Partial Discharges in Dielectric Insulation of Hydro-Generator Coils: Simulation and Experimental Results
Abstract A methodology based on spectral analysis for localization of multiple partial discharges in dielectric region of hydro-generator coils is proposed. This pinpointing of multiple discharges aims to provide means for performing diagnosis of insulating regions of the coil. A numerical model of the structure was developed by using the finite-difference t
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2016-09
-
8. Melhorando o Desempenho Computacional de um Esquema de Diferenças Finitas para as Equações de Maxwell
RESUMO As equações de Maxwell têm um papel crucial na teoria do eletromagnetismo e suas aplicações. Entretanto, nem sempre é possível resolver essas equações de forma analítica. Por isso, precisamos de métodos numéricos para obter soluções aproximadas das equações de Maxwell. O método FDTD (Finite-Diference Time-Domain), proposto por K. Yee,
TEMA (São Carlos). Publicado em: 2016-04
-
9. Semi-analytical formulation for a Unified Time and Frequency Antenna Characterization
AbstractThe definition of parameters that characterize the radiation of electric and magnetic fields for antennas in the time and frequency domain on an unified representation is proposed. The formulation uses a straightforward semi-analytical formulation that can be subsequently applied on the analysis of excited antennas for an arbitrary source with tempor
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2015-06
-
10. Characterization of the radiation pattern of antennas via FDTD and time-domain moment expansion
An alternative method is proposed to characterize the radiation pattern of antennas from an impulse response, based on a moment expansion together with a frequency domain near-to-far-field transformation via a FDTD/CPML solver. The approach introduced in the present work is intended for printed antenna analysis in special cases when the geometries to be mode
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2014-06
-
11. SAR Analysis for handheld mobile phone using DICOM based voxel model
In this paper, Specific Absorption Rates (SAR) inside the human head and hand have been analyzed for a handheld mobile phone operated at GSM 900 band. Both the head and hand are modeled electrically using Digital Imaging and Communication in Medicine (DICOM) formatted CT Scan voxel data considering the electrical parameters of different internal anatomical s
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2013-12
-
12. Characterization of the radiation pattern of antennas using time-domain spherical-multipole and moment expansion
This paper presents results of a time-domain spherical-multipole near-to-far-field transformation together with a moment expansion applied to antenna radiation patterns. The equivalence principle is applied to the tangential fields all over the FDTD/WP-PML spatial grid and the use of the spherical-multipole expansion leads to the near-to-far-field transforma
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2013-12