A hybrid spectral/FDTD method for the electromagnetic analysis of guided waves in periodic structures

Cangellaris, A.C.; Gribbons, M.; Sohos, G.

doi:10.1109/75.242266

Cited by 37 publications

(21 citation statements)

References 3 publications

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“…It should also be pointed out that if a real-valued excitation is used, the final value of (1) is also real-valued. The detailed implementation of the spectral FDTD is as in [7]- [11].…”

Section: Asm-fdtd Methods For Near Field Calculationmentioning

confidence: 99%

“…The "∞" superscript denotes the field due to an infinite phased array of line sources, with phasing wavenumber k x . In the TD the field quantities are complex [7]- [10] and a periodic boundary condition at the edges of the periodic cell are assumed, corresponding to the wavenumber k x . For example, the magnetic field ˆt…”

Section: Asm-fdtd Methods For Near Field Calculationmentioning

confidence: 99%

“…When combined with the FDTD method the new algorithm permits savings of both memory and solution time compared with the standard FDTD method (which must include many periodic cells in the stimulation domain in order to obtain an accurate solution). The FDTD method for periodic structures is here implemented with the "phase shift" boundary conditions in the time domain [7]- [11]. This is a new implementation of the FDTD method that permits the analysis of time-varying excitations in periodic structures illuminated by a plane wave with oblique incidence or by a periodic set of line sources phased to produce a beam at an oblique angle.…”

Section: Introductionmentioning

confidence: 99%

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Directive emission from a single subwavelength aperture in a periodically corrugated silver film

et al. 2007

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Directive emission from a single subwavelength aperture in a periodically corrugated silver film ABSTRACTWe present here an algorithm to evaluate the field in the near zone produced by a finite-size electromagnetic source in a periodic structure, referred to as the array scanning method (ASM) -FDTD method. Using a frequency-dependent silver permittivity model, obtained from measurement at optical and infrared frequencies, we implemented the corresponding modeling equations in the ASM-FDTD algorithm using the Z-transform technique. The developed algorithm is applied to the study of the enhanced radiation of a magnetic line source in a corrugated silver film, and the results indicate that the enhancement is due to the excitation of a leaky mode. We also show that other waves may be excited by the source depending on its location, and how this affects the radiation pattern.

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“…It should also be pointed out that if a real-valued excitation is used, the final value of (1) is also real-valued. The detailed implementation of the spectral FDTD is as in [7]- [11].…”

Section: Asm-fdtd Methods For Near Field Calculationmentioning

confidence: 99%

Section: Asm-fdtd Methods For Near Field Calculationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Directive emission from a single subwavelength aperture in a periodically corrugated silver film

et al. 2007

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“…However, these methods may produce spurious solutions or suffer from instability [8], so the FDTD method has been used in conjunction with other numerical techniques in order to tackle this limitation. In 1993, Aoyagi et al [9] used the Yee algorithm in conjunction with the scalar wave equation to reduce the computations needed to model a Vivaldi antenna, while Cangellaris et al [10] used a hybrid spectral-FDTD method to analyze propagation in anisotropic, inhomogeneous periodic structures. Wang [11] introduced a hybrid ray-FDTD method and used it to investigate scattering from a cavity with a complex termination and wave penetration through inhomogeneous walls.…”

Section: Introductionmentioning

confidence: 99%

Hybrid Computational Scheme for Antenna-Human Body Interaction

Ramli¹,

Abd‐Alhameed²,

See³

et al. 2013

PIER

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Abstract-A new hybrid method of moments (MoM)/finite-difference time-domain (FDTD), with a sub-gridded finite-difference timedomain (SGFDTD) approach is presented. The method overcomes the drawbacks of homogeneous MoM and FDTD simulations, and so permits accurate analysis of realistic applications. As a demonstration, it is applied to the short-range interaction between an inhomogeneous human body and a small UHF RFID antenna tag, operating at 900 MHz. Near-field and far-field performance for the antenna are assessed for different placements over the body. The cumulative distribution function of the radiation efficiency and the absorbed power are presented and analyzed. The algorithm has a five-fold speed advantage over fine-gridded FDTD.

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“…Periodic boundary conditions can be used to simulate structures that have infinite lengths or widths [Alexanian (1996), Cangellaris (1993), Celuch-Marcysiak (1995), Chan (1991), Kelly (1994), Kesler (1996), Navarro (1993), Okoniewski (1993), Tsay (1993)]. When the value of the field just outside of the simulation domain is required, the value of the field at the opposite boundary is used.…”

Section: - Total Fieldmentioning

confidence: 99%

Computational Study and Analysis of Structural Imperfections in 1D and 2D Photonic Crystals

Maskaly

2005

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Dielectric reflectors that are periodic in one or two dimensions, also known as 1D and 2D photonic crystals, have been widely studied for many potential applications due to the presence of wavelength-tunable photonic bandgaps. However, the unique optical behavior of photonic crystals is based on theoretical models of perfect analogues. Little is known about the practical effects of dielectric imperfections on their technologically useful optical properties. In order to address this issue, a finite-difference time-domain (FDTD) code is employed to study the effect of three specific dielectric imperfections in 1D and 2D photonic crystals. The first imperfection investigated is dielectric interfacial roughness in quarter-wave tuned ID photonic crystals at normal incidence. This study reveals that the reflectivity of some roughened photonic crystal configurations can change up to 50% at the center of the bandgap for RMS roughness values around 20% of the characteristic periodicity of the crystal. However, this reflectivity change can be mitigated by increasing the index contrast and/or the number of bilayers in the crystal. In order to explain these results, the homogenization approximation, which is usually applied to single rough surfaces, is applied to the quarter-wave stacks. The results of the homogenization approximation match the FDTD results extremely well, suggesting that the main role of the roughness features is to grade the refractive index profile of the interfaces in the photonic crystal rather than diffusely scatter the incoming light. This result also implies that the amount of incoherent reflection from the roughened quarterwave stacks is extremely small. This is confirmed through direct extraction of the amount of incoherent power from the FDTD calculations. Further FDTD studies are done on the entire normal incidence bandgap of roughened ID photonic crystals. These results reveal a narrowing and red-shifting of the normal incidence bandgap with increasing RMS roughness. Again, the homogenization approximation is able to predict these results. The problem of surface scratches on ID photonic crystals is also addressed. Although the reflectivity decreases are lower in this study, up to a 15% change in reflectivity is observed in certain scratched photonic crystal structures. However, this reflectivity change can be significantly decreased by adding a low index protective coating to the surface of the photonic crystal. Again, application of homogenization theory to these structures confirms its predictive power for this type of imperfection as well. Additionally, the problem of acircular pores in 2D photonic crystals is investigated, 3 showing that almost a 50% change in reflectivity can occur for some structures.Furthermore, this study reveals trends that are consistent with the D simulations: parameter changes that increase the absolute reflectivity of the photonic crystal will also increase its tolerance to structural imperfections. Finally, experimental reflectance spectra from roughened ...

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A hybrid spectral/FDTD method for the electromagnetic analysis of guided waves in periodic structures

Cited by 37 publications

References 3 publications

Directive emission from a single subwavelength aperture in a periodically corrugated silver film

Directive emission from a single subwavelength aperture in a periodically corrugated silver film

Hybrid Computational Scheme for Antenna-Human Body Interaction

Computational Study and Analysis of Structural Imperfections in 1D and 2D Photonic Crystals

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