Investigation of numerical dispersion with time step of the FDTD methods: avoiding erroneous conclusions

Cheng, Yu; Chen, Guangzhi; Wang, Xiang-hua; Yang, Shunchuan

doi:10.1049/mia2.12068

Cited by 5 publications

(5 citation statements)

References 40 publications

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“…Also, the FDTD method is widely used in electromagnetic field analysis, such as for specific absorption rate (SAR) evaluation, so the reliability of the FDTD method can be confirmed from several related works [20,21]. An error analysis of the FDTD method was conducted in [22], where it was shown that the FDTD calculation can achieve an acceptable calculation error in a numerical model. A model used in our electromagnetic field simulation is shown in Figure 1 and the parameters used are shown in Table 1.…”

Section: Examination Of Various Parameters Using Electromagnetic Fiel...mentioning

confidence: 99%

Development of a Wearable System for the Detection of Ingestible Medication Based on Electromagnetic Waves

Hoshino,

Hyry,

Kobayashi

et al. 2024

Electronics

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Managing medication status solves related complications and prevents increases in medical costs due to the improper management of prescriptions. An ingestible sensor can be used to confirm a patient’s real-time medical status by measuring the electromagnetic waves transmitted from an ingested medication from outside of the human body. However, concerns about costs of delivery arise, as it would be necessary to attach a sensor to each ingested medication. In this study, we focused on using an electromagnetic (EM) imaging method which can estimate the internal structure of various objects using a scattered electric field. With this method we can detect medication as it does not require the installation of a sensor. At first we performed an electromagnetic field simulation and based on the results we experimentally measured the external electric field, which changes with the medicine. Then, we evaluated the accuracy of the detection method by calculating the difference between the detection rate with the proposed detection method against a more conventional method. The results indicate the possibility of achieving a more than 20% higher accuracy than the conventional detection method with our proposed method using electromagnetic waves.

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Section: Examination Of Various Parameters Using Electromagnetic Fiel...mentioning

confidence: 99%

Development of a Wearable System for the Detection of Ingestible Medication Based on Electromagnetic Waves

Hoshino,

Hyry,

Kobayashi

et al. 2024

Electronics

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“…Figure 3 also shows that both SE frequency dependencies have unphysical oscillations which are caused by the numerical dispersion of the FDTD method. This issue arises from the difference between wave propagation in the actual physical medium and in the discrete FDTD mesh and can be reduced by increasing computational cost [40]. Henceforward, we decided not to eliminate the errors associated with the numerical dispersion since the achieved calculation accuracy is sufficient for this study.…”

Section: Simulation Of Shield System Elementsmentioning

confidence: 99%

On Symmetry and Asymmetry in Nested Electromagnetic Shields

et al. 2023

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This work focuses on the study of shield systems consisting of nested enclosures. In the first step, using FDTD simulations and measurements in an anechoic chamber, we investigate the shielding effectiveness (SE) of the system of two nested rectangular enclosures in the frequency range of up to 3 GHz. It is shown for the first time that for a number of frequencies, the SE of the nested shields can be improved by 40–50 dB due to the asymmetric arrangement of the enclosures, their electrical connection, and the mutually perpendicular arrangement of the apertures. Next, we analyze the emissions from the electromagnetic radiation sources in the presence and absence of a nested shield system. The results show that a nested shield system may not attenuate the emission amplitude but increases it by more than 58 dB at the resonant frequencies of the enclosures. Then, we prove that a single enclosure can have a higher SE than the same enclosure as a part of a poorly designed nested shield system. The final part of the article formulates practical recommendations for the design of nested shield configurations.

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“…The values of the electric and magnetic fields are calculated at each point of the structure and at each instant. The time steps lead to small numerical errors, but at long times the numerical dispersion can severely degrade the accuracy and even be totally unacceptable [85]. The DDA has been extended to the temporal regime.…”

Section: Dda In Time Domainmentioning

confidence: 99%

The Discrete Dipole Approximation: A Review

Chaumet

2022

Mathematics

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There are many methods for rigorously calculating electromagnetic diffraction by objects of arbitrary shape and permittivity. In this article, we will detail the discrete dipole approximation (DDA) which belongs to the class of volume integral methods. Starting from Maxwell’s equations, we will first present the principle of DDA as well as its theoretical and numerical aspects. Then, we will discuss the many developments that this method has undergone over time and the numerous applications that have been developed to transform DDA in a very versatile method. We conclude with a discussion of the strengths and weaknesses of the DDA and a description of the freely available DDA-based electromagnetic diffraction codes.

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Investigation of numerical dispersion with time step of the FDTD methods: avoiding erroneous conclusions

Cited by 5 publications

References 40 publications

Development of a Wearable System for the Detection of Ingestible Medication Based on Electromagnetic Waves

Development of a Wearable System for the Detection of Ingestible Medication Based on Electromagnetic Waves

On Symmetry and Asymmetry in Nested Electromagnetic Shields

The Discrete Dipole Approximation: A Review

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