Interpolation techniques to improve the accuracy of the plane wave excitations in the finite difference time domain method

Oğuz, U.; Gürel, L.

doi:10.1029/97rs02515

Cited by 30 publications

(20 citation statements)

References 18 publications

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“…For each excitation, a monochromatic wave is applied at the location of each antenna. The amplitudes and phases of steady-state fields are then extracted by a fast two-point algorithm [59]. A dual-mesh [60] scheme is also used for these reconstructions.…”

Section: Resultsmentioning

confidence: 99%

Microwave Image Reconstruction of Tissue Property Dispersion Characteristics Utilizing Multiple-Frequency Information

Fang

Meaney

Paulsen

2004

IEEE Trans. Microwave Theory Techn.

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A multiple-frequency-dispersion reconstruction algorithm utilizing a Gauss-Newton iterative strategy is presented for microwave imaging. This algorithm facilitates the simultaneous use of multiple-frequency measurement data in a single image reconstruction. Using the stabilizing effects of the low-frequency measurement data, higher frequency data can be included to reconstruct images with improved resolution. The parameters reconstructed in this implementation are now frequency-independent dispersion coefficients instead of the actual properties and may provide new diagnostic information. In this paper, large high-contrast objects are successfully constructed utilizing assumed simple dispersion models for both simulation and phantom cases for which the traditional single-frequency algorithm previously failed. Consistent improvement in image quality can be observed by involving more frequencies in the reconstruction; however, there appears to be a limit to how closely spaced the frequencies can be chosen while still providing independent new information. Possibilities for fine-tuning the image reconstruction performance in this context include: 1) variations of the assumed dispersion model and 2) Jacobian matrix column and row weighting schemes. Techniques for further reducing the forward solution computation time using time-domain solvers are also briefly discussed. The proposed dispersion reconstruction technique is quite general and can also be utilized in conjunction with other Gauss-Newton-based algorithms including the log-magnitude phase-form algorithm.Index Terms-Column weighting, finite-difference time-domain (FDTD) method, microwave imaging, multiple frequency-dispersion reconstruction (MFDR), row weighting.

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Section: Resultsmentioning

confidence: 99%

Microwave Image Reconstruction of Tissue Property Dispersion Characteristics Utilizing Multiple-Frequency Information

Fang

Meaney

Paulsen

2004

IEEE Trans. Microwave Theory Techn.

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“…For example, in the free space, the incident field for two-dimensional (2-D) and three-dimensional (3-D) computation spaces can be obtained from 1-D incident field array (IFA) via interpolation [10], [11]. For non-dispersive stratified media, the excitation at the TFSF boundary can be obtained by interpolating from a single 1-D auxiliary FDTD based on the transmission delay time [12], [13].…”

Section: Introductionmentioning

confidence: 99%

Introduction of Oblique Incidence Plane Wave to Stratified Lossy Dispersive Media for FDTD Analysis

Chen

2012

IEEE Trans. Antennas Propagat.

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In the application of finite-difference time-domain (FDTD) method to the wideband plane wave scattering analysis of objects embedded in stratified lossy dispersive media, it is a challenge to solve the obliquely incident wave. In this work, a novel configuration of auxiliary one-dimensional (1-D) FDTD grids is proposed to provide the obliquely incident plane wave at the total-field scattered-field (TFSF) boundary in stratified lossy dispersive media. Thus a closed TFSF boundary is formed, where the incident waves are directly obtained from the auxiliary simulations without any interpolation. The formulations of the auxiliary simulations are presented by the modified 1-D Maxwell's equations. Given the dispersion characteristic, perfectly matched layer (PML) is implemented to the 1-D simulations. Examples demonstrate the effectiveness of the proposed technique of obliquely incident wave introduction. Index Terms-Dispersive media, finite-difference time-domain (FDTD) methods, perfectly matched layer, scattering.

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“…When coupling between the auxiliary and the main grids, a field leaks into the scattered field region because their numerical dispersion relations are different. Improvements to the IFA have been made by various researchers, by either modifying the dispersion properties [2], or increasing the sampling in time and/or space and applying signal processing techniques [3]. To date these improvements only achieve a dynamic ranges from −30dB to −70dB.…”

Section: Introductionmentioning

confidence: 99%

A 1D multipoint auxiliary propagator (1D-MAP) for sourcing plane waves for FDTD

Tan

Potter

2007

2007 IEEE Antennas and Propagation Society International Symposium

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Interpolation techniques to improve the accuracy of the plane wave excitations in the finite difference time domain method

Abstract: The relative accuracies and efficiencies of these two excitation schemes are compared, and it has been shown that higher-order interpolation techniques can be used to improve the accuracy of the IFA scheme, which is already quite efficient.

Cited by 30 publications

References 18 publications

Microwave Image Reconstruction of Tissue Property Dispersion Characteristics Utilizing Multiple-Frequency Information

Microwave Image Reconstruction of Tissue Property Dispersion Characteristics Utilizing Multiple-Frequency Information

Introduction of Oblique Incidence Plane Wave to Stratified Lossy Dispersive Media for FDTD Analysis

A 1D multipoint auxiliary propagator (1D-MAP) for sourcing plane waves for FDTD

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