The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform
L.e. Rickard Petersson - One of the best experts on this subject based on the ideXlab platform.
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Total-and Scattered-Field decomposition technique for the finite-element time-domain method
IEEE Transactions on Antennas and Propagation, 2006Co-Authors: D.j. Riley, L.e. Rickard PeterssonAbstract:A new finite-element time-domain (FETD) volumetric plane-wave excitation method for use with a total- and Scattered-Field decomposition (TSFD) is rigorously described. This method provides an alternative to the traditional Huygens' surface approaches commonly used to impress the incident Field into the total-Field region. Although both the volumetric and Huygens' surface formulations theoretically provide for zero leakage of the impressed wave into the Scattered-Field region, the volumetric method provides a simple path to numerically realize this. In practice, the level of leakage for the volumetric scheme is determined by available computer precision, as well as the residual of the matrix solution. In addition, the volumetric method exhibits nearly zero dispersion error with regard to the discrete incident Field.
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Total- and Scattered-Field decomposition technique for the finite-element time-domain method
2005 IEEE Antennas and Propagation Society International Symposium, 2005Co-Authors: D.j. Riley, L.e. Rickard PeterssonAbstract:A total- and Scattered-Field decomposition (TSFD) technique for the finite-element time-domain (FETD) method is described. This formulation leads to both a volumetric excitation method and a Huygens' surface excitation method to impress the incident Field in the total-Field region. Leakage suppression into the Scattered-Field region on the order of -250 dB has been obtained, independent of the mesh density and the propagation angle. In addition, in a free-space environment, the relative error between the calculated total Field and the discrete incident Field is also on the order of -250 dB for the volumetric excitation scheme. Consequently, this total- and Scattered-Field approach can provide accuracy that is comparable to a pure Scattered-Field formulation. Both free space and air-earth interfaces are considered
Runren Zhang - One of the best experts on this subject based on the ideXlab platform.
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mixed total Field Scattered Field based discontinuous galerkin frequency domain method for subsurface sensing
IEEE Transactions on Geoscience and Remote Sensing, 2019Co-Authors: Qiwei Zhan, Runren ZhangAbstract:To model the responses of electromagnetic surveys for geophysical subsurface sensing, a mixed total Field/Scattered Field-based discontinuous Galerkin frequency-domain (TF/SF DGFD) method is proposed in this paper. The proposed TF/SF DGFD method is implemented at a subdomain level based on the domain decomposition technique. Different subdomains can employ either the TF DGFD framework or the SF DGFD framework, which are then coupled through the Riemann transmission condition. To balance the computation efficiency and accuracy for practical applications, the proposed method prefers to using the SF DGFD framework for subdomains with sources and using the TF DGFD framework for the remaining subdomains. At the interfaces between total Field and Scattered Field subdomains, the Riemann transmission condition is slightly modified by incorporating the background Fields due to the physically imposed sources in the background media. In this way, the proposed method only requires surface integrals of the background Fields as extra overhead instead of elementwise integration of the scattering objects for the purely Scattered Field-based method, which can improve the computational efficiency. Also, it is more accurate than the purely TF DGFD method given the same mesh. Numerical examples are studied to examine the performance of the proposed method, which is proven to have better accuracy than the TF DGFD method. The TF/SF DGFD method will facilitate modeling of electromagnetic surveys under complicated geophysical environments for subsurface sensing.
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Mixed Total Field/Scattered Field-Based Discontinuous Galerkin Frequency-Domain Method for Subsurface Sensing
IEEE Transactions on Geoscience and Remote Sensing, 2019Co-Authors: Qiwei Zhan, Runren ZhangAbstract:To model the responses of electromagnetic surveys for geophysical subsurface sensing, a mixed total Field/Scattered Field-based discontinuous Galerkin frequency-domain (TF/SF DGFD) method is proposed in this paper. The proposed TF/SF DGFD method is implemented at a subdomain level based on the domain decomposition technique. Different subdomains can employ either the TF DGFD framework or the SF DGFD framework, which are then coupled through the Riemann transmission condition. To balance the computation efficiency and accuracy for practical applications, the proposed method prefers to using the SF DGFD framework for subdomains with sources and using the TF DGFD framework for the remaining subdomains. At the interfaces between total Field and Scattered Field subdomains, the Riemann transmission condition is slightly modified by incorporating the background Fields due to the physically imposed sources in the background media. In this way, the proposed method only requires surface integrals of the background Fields as extra overhead instead of elementwise integration of the scattering objects for the purely Scattered Field-based method, which can improve the computational efficiency. Also, it is more accurate than the purely TF DGFD method given the same mesh. Numerical examples are studied to examine the performance of the proposed method, which is proven to have better accuracy than the TF DGFD method. The TF/SF DGFD method will facilitate modeling of electromagnetic surveys under complicated geophysical environments for subsurface sensing.
K. Goto - One of the best experts on this subject based on the ideXlab platform.
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Uniform asymptotic solutions for Scattered Field by a coated conducting cylinder
2013 International Symposium on Electromagnetic Theory, 2013Co-Authors: K. GotoAbstract:We derive two kinds of uniform asymptotic solutions for the high-frequency Scattered Field when a cylindrical wave is incident on a coated conducting cylinder covered by a thin lossy dielectric material. We show that the extended UTD (uniform geometrical theory of diffraction) solution and the modified UTD solution derived by retaining the higher order term can be applied uniformly in the transition region near the shadow boundary and in the deep shadow region in which the conventional UTD solution produces the substantial errors. The validity of the uniform asymptotic solutions derived here is confirmed by comparing with the exact solution obtained from the eigenfunction expansion.
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High-frequency asymptotic analysis for Scattered Field by a conducting cylinder
2013 International Symposium on Electromagnetic Theory, 2013Co-Authors: K. GotoAbstract:In this study, we consider the high-frequency asymptotic analysis methods for the Scattered Field when a cylindrical wave is incident on a conducting circular cylinder. We derive the asymptotic solution applicable in each of the transition regions divided by the shadow boundary into the shadow and the lit side. The asymptotic solutions include a novel extended Pekeris caret function to which the second order term in the argument of the exponential in the integrand is added as compared with the Pekeris caret function including the UTD (uniform GTD) solution. By applying the residue theorem and the saddle point technique to the novel extended Pekeris caret function, we derive respectively the surface diffracted ray solution and the reflected geometrical ray solution which are effective exterior to the transition regions. The validity of the various asymptotic solutions derived here is confirmed by comparing with the exact solution.
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Asymptotic solution for transient Scattered Field by a cylindrically curved conducting surface
2009 IEEE Antennas and Propagation Society International Symposium, 2009Co-Authors: K. Goto, T. Kawano, T. IshiharaAbstract:We have derived the time-domain asymptotic solution for the transient Scattered Field by the cylindrically curved conducting surface by extending the corresponding frequency-domain asymptotic solution. The validity and utility of the time-domain asymptotic solution derived here have been confirmed by comparing with the reference solution. We have shown that the time-domain asymptotic solution, which is represented by the summation of each pulse element, is easy to understand the physical insight of the scattering phenomena by the cylindrically curved conducting surface.
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Novel Time-Domain Uniform Asymptotic Solution for Transient Scattered Field
2007 International Conference on Electromagnetics in Advanced Applications, 2007Co-Authors: K. Goto, H. Yamada, T. Ajiki, T. Kawano, T. IshiharaAbstract:Novel time-domain uniform asymptotic solution (novel TD-UAS) for transient Scattered Field excited by a cylindrically curved conducting open surface with a constant radius of curvature is presented in this paper. We shall derive the novel TD-UAS, which is applicable in the transition regions including the reflection boundary and the shadow boundary, by applying only the Fourier transform method. The accuracy and the validity of the novel TD-UAS are confirmed by comparing both with the reference solution calculated numerically from the combination of the method of moment and the FFT numerical code and with the hybrid experimental-numerical results obtained from the combination of the experimental results for the frequency-domain Scattered Field and the FFT numerical code.
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Asymptotic analysis of transient Scattered Field by a cylindrically curved conducting open surface
2006 IEEE Antennas and Propagation Society International Symposium, 2006Co-Authors: K. Goto, T. Ajiki, T. IshiharaAbstract:In this research, the time-domain uniform asymptotic solution for the Scattered Field by a cylindrically curved conducting open surface was derived. The time-domain uniform asymptotic solution consists of the edge diffracted rays, the surface diffracted rays, the geometrical rays, the whispering gallery (WG) mode radiation Field, and the combination of these waves. Comparisons of the time-domain uniform asymptotic solution with the reference solution calculated numerically from the combination of the frequency-domain numerical solution by the method of moment and fast Fourier transform (FFT) code confirm the validity and utility of the proposed time-domain uniform asymptotic solution
D.j. Riley - One of the best experts on this subject based on the ideXlab platform.
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Total-and Scattered-Field decomposition technique for the finite-element time-domain method
IEEE Transactions on Antennas and Propagation, 2006Co-Authors: D.j. Riley, L.e. Rickard PeterssonAbstract:A new finite-element time-domain (FETD) volumetric plane-wave excitation method for use with a total- and Scattered-Field decomposition (TSFD) is rigorously described. This method provides an alternative to the traditional Huygens' surface approaches commonly used to impress the incident Field into the total-Field region. Although both the volumetric and Huygens' surface formulations theoretically provide for zero leakage of the impressed wave into the Scattered-Field region, the volumetric method provides a simple path to numerically realize this. In practice, the level of leakage for the volumetric scheme is determined by available computer precision, as well as the residual of the matrix solution. In addition, the volumetric method exhibits nearly zero dispersion error with regard to the discrete incident Field.
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Total- and Scattered-Field decomposition technique for the finite-element time-domain method
2005 IEEE Antennas and Propagation Society International Symposium, 2005Co-Authors: D.j. Riley, L.e. Rickard PeterssonAbstract:A total- and Scattered-Field decomposition (TSFD) technique for the finite-element time-domain (FETD) method is described. This formulation leads to both a volumetric excitation method and a Huygens' surface excitation method to impress the incident Field in the total-Field region. Leakage suppression into the Scattered-Field region on the order of -250 dB has been obtained, independent of the mesh density and the propagation angle. In addition, in a free-space environment, the relative error between the calculated total Field and the discrete incident Field is also on the order of -250 dB for the volumetric excitation scheme. Consequently, this total- and Scattered-Field approach can provide accuracy that is comparable to a pure Scattered-Field formulation. Both free space and air-earth interfaces are considered
Glenn S. Smith - One of the best experts on this subject based on the ideXlab platform.
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a total Field Scattered Field plane wave source for the fdtd analysis of layered media
IEEE Transactions on Antennas and Propagation, 2008Co-Authors: Ilker R. Capoglu, Glenn S. SmithAbstract:A total-Field/Scattered-Field (TF/SF) plane-wave source is developed for the finite-difference time-domain analysis of general (possibly lossy) planar layered media. A 1-D auxiliary grid is created to generate the incident Field in the presence of the layered medium. Inhomogeneous plane waves are also allowed for lossless layers and narrowband excitation.
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A Total-Field/Scattered-Field Plane-Wave Source for the FDTD Analysis of Layered Media
IEEE Transactions on Antennas and Propagation, 2008Co-Authors: Ilker R. Capoglu, Glenn S. SmithAbstract:A total-Field/Scattered-Field (TF/SF) plane-wave source is developed for the finite-difference time-domain analysis of general (possibly lossy) planar layered media. A 1-D auxiliary grid is created to generate the incident Field in the presence of the layered medium. Inhomogeneous plane waves are also allowed for lossless layers and narrowband excitation.
