Electromagnetic Modeling of Metamaterials

Uno, Toru

doi:10.1587/transcom.e96.b.2340

Cited by 7 publications

(5 citation statements)

References 29 publications

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“…The advantage of using the complex electromagnetic field instead of the Hilbert transform is that it can handle a broader range of physical models in electromagnetic problems. For instance, the direct calculation of the complex electromagnetic field enables periodic structures illuminated by oblique incident waves to be modeled . In contrast, the Hilbert transform scheme cannot be applied for the optimization of such models because it does not generate a phasor representation of the solution at each time step, which is essential for the implementation of Floquet or periodic boundary conditions.…”

Section: Formulation Of the Optimization Methodsmentioning

confidence: 99%

“…Usually, in the FDTD method, only the real part of the electromagnetic field is calculated. A direct extension for calculation of the complex field has also been formulated to model a periodic structure illuminated by oblique incident waves . These methods are called the Sine‐Cosine Method for single‐frequency problems, and Split‐Field FDTD method for broadband frequency problems.…”

Section: Formulation Of the Optimization Methodsmentioning

confidence: 99%

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A design method of spatiotemporal optical pulse using level‐set based time domain topology optimization

Yasuda

Yamada

Nishiwaki

2018

Numerical Meth Engineering

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Recently, two emerging areas of photonics research, ultrafast photonics, and nanophotonics have started to come together. One of the main problems in this field is the precise control of spatial and temporal profiles of the optical pulses.In this paper, we propose a design method for user-specified spatiotemporal optical pulses using a level set-based time-domain topology optimization method.In the proposed method, the optimization problem is formulated based on time domain Maxwell equations so that the spatiotemporal optical pulses can be treated directly. The objective function is defined using the envelope information of the pulses, and an efficient way to calculate this information, based on calculations of the complex electromagnetic field, is introduced. A level set-based topology optimization method is applied to obtain optimized configurations.Using the proposed method, the spatiotemporal user-specified pulse profiles can be designed by modifying the structural details of the nanostructures through which the pulses propagate. As a simple example, we demonstrate that the optimized structures focus optical pulses into a single or multiple focal points with a user-specified pulse-width. The results show that the proposed method is able to design highly controlled spatiotemporal optical pulses by engineering the nanophotonic structure. KEYWORDSfinite difference methods, level sets, topology design INTRODUCTIONNanophotonics and ultrafast photonics are main subjects of research in the current photonics research field. Nanophotonics is the study of the behavior of light on the nanometer scale and of the interaction of nanometer-scale objects with light. Nanophotonics is an emerging technology with many applications 1-4 such as surface-enhanced Raman scattering, near field optical microscopy, and metamaterials. On the other hand, ultrafast photonics is the study of light and its interaction with matter on short timescales of less than a picosecond. 5,6 The main interest in this field is to investigate the processes that occur in atoms, molecules, and solids, such as the dynamics of and correlations between electrons.Nanophotonics and ultrafast photonics, which developed independently, have recently started to merge. [7][8][9] In the vicinity of a nanostructure, ultrafast pulses drastically change their spatial and temporal profiles. In other words, the spatiotemporal optical pulse profile can be arbitrarily changed by adjusting the surrounding nanostructure. Spatially and temporally controlled ultrafast pulses potentially offer an efficient way to enhance light-matter interactions at the nanoscale and provide a promising platform for information processing.Int J Numer Methods Eng. 2019;117:605-622.wileyonlinelibrary.com/journal/nme

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Section: Formulation Of the Optimization Methodsmentioning

confidence: 99%

Section: Formulation Of the Optimization Methodsmentioning

confidence: 99%

A design method of spatiotemporal optical pulse using level‐set based time domain topology optimization

Yasuda

Yamada

Nishiwaki

2018

Numerical Meth Engineering

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“…Analytical techniques contributed to simplify engineering models and solving them in an integrated solution using different techniques, including Simple Cavity Model, Wire Grid Model, and Green Function Method [16]. The Finite Difference Time Domain Method FDTD, Finite Difference Frequency Domain Method FDFD, Method of Moments MoM, and Finite Element Method FEM are example for numerical techniques use to solve field equations which are directly subject to imposed boundary constraints by the geometric structure [17]. The FDTD method has a prominent place among the numerical techniques that were used in electromagnetic analysis over the last two decades.…”

Section: Theoretical Partmentioning

confidence: 99%

Bandwidth enhancement of cylindrical triangular microstrip antenna using a stacked technique

2022

ijp

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This paper presents a new design of a conformal microstrip antenna operating in a dual-band for several applications including Wireless Local Area Networks (WLAN), Wi-Fi networks, and Wireless Body Area Networks (WBAN). The proposed design was achieved using the stacked patch technique on a conformal microstrip antenna. One of the patches is square-shaped and the other is triangularshaped constructed on a cylindrical surface with a 50 mm radius using a substrate with a permittivity of 2.98. The proposed design can be called a stacked square-shaped triangular cylindrical microstrip antenna. The operating resonant frequencies have been set at 623 and 795 GHz. For the standard antenna, the bandwidths of dual-band are equal to 0.65 % and 0.92 %. By adding an air gap between the ground plane and substrate, bandwidths are enhanced to 6.15 % and 3.07 %, and then increasing the substrates' thickness leads to more improvement of the percentage of bandwidth to 40.2 % and 24.12 %. The Finite-Difference in Time Domain (FDTD) method is used to design and analyze the proposed antenna.

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“…To reduce calculation time, prediction methods have been applied to the FDTD method. One of the prediction methods is using the autoregressive moving average (ARMA) model [5] to predict convergence values. It can reduce the calculation time of the FDTD analysis; the effectiveness of the ARMA model in the FDTD analysis has been verified [2,5].…”

Section: Introductionmentioning

confidence: 99%

“…One of the prediction methods is using the autoregressive moving average (ARMA) model [5] to predict convergence values. It can reduce the calculation time of the FDTD analysis; the effectiveness of the ARMA model in the FDTD analysis has been verified [2,5]. However, the ARMA model has not been applied to FDTD radiation pattern analysis because the radiation patterns calculation requires multi-dimensional (time and space) data.…”

Section: Introductionmentioning

confidence: 99%

Acceleration of FDTD radiation pattern calculation using two-dimensional ARMA

2021

Self Cite

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In recent years, the finite-difference time-domain (FDTD) method has been widely employed for analyzing various electromagnetic problems, including low-frequency problems. It provides accurate results in most cases, but it requires relatively long calculation time for slow convergence problems, such as array antennas. For this reason, the autoregressive moving average (ARMA) model has been applied to the FDTD analysis to reduce calculation time. However, it has not been applied to FDTD radiation pattern analysis because the radiation patterns calculation requires multi-dimensional (time and space) data. In this letter, twodimensional ARMA is applied to FDTD radiation pattern analysis to reduce the calculation time. We confirm effectiveness of the method by calculating the radiation pattern of Yagi-Uda antenna.

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Electromagnetic Modeling of Metamaterials

Cited by 7 publications

References 29 publications

A design method of spatiotemporal optical pulse using level‐set based time domain topology optimization

A design method of spatiotemporal optical pulse using level‐set based time domain topology optimization

Bandwidth enhancement of cylindrical triangular microstrip antenna using a stacked technique

Acceleration of FDTD radiation pattern calculation using two-dimensional ARMA

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