FDTD accuracy improvement by incorporation of 3D edge singularities

Huynh, Ngoc-Hoa; Heinrich, W.

doi:10.1109/mwsym.1999.780257

Cited by 8 publications

(4 citation statements)

References 7 publications

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“…Furthermore, the effect of the triple junctions would remain, so no improvement would be achieved overall. Other numerical methods like finite difference analysis do not provide sufficient approaches yet to deal with sensitivities but rather discretization errors of electric field strength 67–69 …”

Section: Discussionmentioning

confidence: 99%

“…Other numerical methods like finite difference analysis do not provide sufficient approaches yet to deal with sensitivities but rather discretization errors of electric field strength. [67][68][69] In the case of FEM, two of these existing methods, the LM and the VM, were altered in this study to also account for singularities in sensitivities. Overall, both methods provide consistent results in terms of the size and shape of the SVs.…”

Section: Sensitivitiesmentioning

confidence: 99%

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Spatial sensitivity distribution assessment and Monte Carlo simulations for needle‐based bioimpedance imaging during venipuncture using the finite element method

Atmaca,

Liu,

et al. 2024

Numer Methods Biomed Eng

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Despite being among the most common medical procedures, needle insertions suffer from a high error rate. Impedance measurements using electrode‐equipped needles offer promise for improved tissue targeting and reduced errors. Impedance visualization usually requires an extensive pre‐measured impedance dataset for tissue differentiation and knowledge of the electric fields contributing to the resulting impedances. This work presents two finite element simulation approaches for both problems. The first approach describes the generation of a multitude of impedances with Monte Carlo simulations for both, homogeneous and inhomogeneous tissue to circumvent the need to rely on previously measured data. These datasets could be used for tissue discrimination. The second method describes the simulation of the spatial sensitivity distribution of an electrode layout. Two singularity analysis methods were employed to determine the bulk of the sensitivity within a finite volume, which in turn enables consistent 3D visualization. The modeled electrode layout consists of 12 electrodes radially placed around a hypodermic needle. Electrical excitation was simulated using two neighboring electrodes for current carriage and voltage pickup, which resulted in 12 distinct bipolar excitation states. Both, the impedance simulations and the respective singularity analysis methods were compared with each other. The results show that the statistical spread of impedances is highly dependent on the tissue type and its inhomogeneities. The bounded bulk of sensitivities of both methods are of similar extent and symmetry. Future models should incorporate more detailed tissue properties such as anisotropy or changing material properties due to tissue deformation to gain more accurate predictions.

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Section: Discussionmentioning

confidence: 99%

Section: Sensitivitiesmentioning

confidence: 99%

Spatial sensitivity distribution assessment and Monte Carlo simulations for needle‐based bioimpedance imaging during venipuncture using the finite element method

Atmaca,

Liu,

et al. 2024

Numer Methods Biomed Eng

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“…The approximation of step changes in , while convenient mathematically, is known to produce singularities in local fields and their gradients at internal corners and edges [20]. These singularities are square integrable, as is required for conservation of energy, but are generally not fully resolvable with standard FDTD, FEM, and RCWA methods, though specialized methods have been proposed to treat some of the singularities in particular geometries [21][22][23]. The cylindrical geometry considered here contains no corners and the active region of GaAs is convex, so the field singularities inside the nanowire material are relatively benign, but they are not accurately modeled here.…”

Section: Substratementioning

confidence: 99%

Efficient wave optics modeling of nanowire solar cells using rigorous coupled-wave analysis

Robertson¹,

LaPierre²,

Krich³

2019

Opt. Express

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We investigate the accuracy of rigorous coupled-wave analysis (RCWA) for near-field computations within cylindrical GaAs nanowire solar cells and discover excellent accuracy with low computational cost at long incident wavelengths but poor accuracy at short incident wavelengths. These near fields give the carrier generation rate, and their accurate determination is essential for device modeling. We implement two techniques for increasing the accuracy of the near fields generated by RCWA and give some guidance on parameters required for convergence along with an estimate of their associated computation times. The first improvement removes Gibbs phenomenon artifacts from the RCWA fields, and the second uses the extremely well-converged far-field absorption to rescale the local fields. These improvements allow a computational speedup between 30 and 1000 times for spectrally integrated calculations, depending on the density of the near fields desired. Some spectrally resolved quantities, especially at short wavelengths, remain expensive, but RCWA is still an excellent method for performing those calculations. These improvements open up the possibility of using RCWA for low-cost optical modeling in a full optoelectronic device model of nanowire solar cells.

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“…This approach is used in [4] and [5] for the two-dimensional (2-D) case and where the edge of the strip coincides with the edges of the FDTD cells. A similar approach is used in [6] to model a coplanar line and is extended in [7] to the analysis of a three-dimensional (3-D) coplanar open stub, including the effects of a right angle bend.…”

Section: Comparison With Previous Workmentioning

confidence: 99%

The treatment of geometrically small structures in FDTD by the modification of assigned material parameters

Railton

Paul

Craddock

et al. 2005

IEEE Trans. Antennas Propagat.

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Abstract-A number of different improvements to the analysis by finite-difference time-domain (FDTD) of small structures, such as wires, strips and slots have been proposed in the literature. One of these methods takes account of the fringing fields associated with metal edges and wires by empirically modifying the assigned material parameters in neighboring cells. In this contribution it is shown that, in many cases, it is possible to derive these modified assigned material parameters (MAMPs) analytically. In this form, the approach provides an alternative, and novel, way of incorporating Static Field Solutions into the FDTD method which has advantages of simplicity and robustness over existing techniques. Results are presented for a number of structures including wire transmission lines and a microstrip patch antenna.Index Terms-Author, please supply your own keywords or send a blank e-mail to keywords@ieee.org to receive a list of suggested keywords.

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FDTD accuracy improvement by incorporation of 3D edge singularities

Cited by 8 publications

References 7 publications

Spatial sensitivity distribution assessment and Monte Carlo simulations for needle‐based bioimpedance imaging during venipuncture using the finite element method

Spatial sensitivity distribution assessment and Monte Carlo simulations for needle‐based bioimpedance imaging during venipuncture using the finite element method

Efficient wave optics modeling of nanowire solar cells using rigorous coupled-wave analysis

The treatment of geometrically small structures in FDTD by the modification of assigned material parameters

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