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Designing multilayered wire-grid polarizers using a monochromatic recursive convolution finite-difference time-domain algorithm

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JOURNAL OF THE SOCIETY FOR INFORMATION DISPLAY 2014年第2期22卷 98-105页

作者： Banerjee, Saswatee Sumitomo Chem Co Ltd Adv Mat Res Lab Tsukuba Ibaraki Japan

Multilayered wire-grid polarizers (WGP) find application as low-reflection polarizers in projection-type liquid crystal display devices. A multilayered WGP is formed by adding thin layers on top of the metal ridges of an ordinary WGP. The ordinary WGP consists of a periodic array of parallel metal ridges, where the period of the array and the width of any individual metal ridge are typically less than the wavelength of the incident light. Such WGPs are often used as efficient polarizers. However, in certain applications, it is important to reduce the reflection from the WGP while preserving the polarization efficiency. One of the ways to achieve this goal is to add thin layers on top of the metal ridges of the ordinary WGP. The reduction in reflection from the multilayered WGP depends on the number and material of these additional layers. In this paper, we describe a design method for multilayered WGPs based on an effective medium theory, thin-film computation method and a monochromatic recursive convolution finite-difference time-domain algorithm. The goal of design process is to identify suitable materials and thicknesses for the additional thin layers needed to lower the reflection appreciably. The design method is explained with the help of bilayered WGPs.

关键词： wire-grid polarizers WGP multilayered subwavelength gratings optical design finite-difference time-domain algorithm FDTD

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A novel contour-path finite-difference time-domain (CPFDTD) algorithm for modeling objects with curved surfaces

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MICROWAVE AND OPTICAL TECHNOLOGY LETTERS 2001年第4期28卷 285-287页

作者： Min, Y Kil, B Lee, S Hanyang Univ Div Elect & Comp Engn Seoul 133791 South Korea

A novel CPFDTD algorithm for modeling smooth curved surfaces is presented. This scheme subdivides electric fields on the distorted grid into the extended contour field, the nondistorted field, and the quasiavailable field to avoid the collinear borrowing approximation. Several earlier methods are applied to the E-plane sectoral horn antenna to obtain far-field patterns. To show the validity and applicability of our method, computed far-field patterns are compared with measured values. (C) 2001 John Wiley & Sons, Inc.

关键词： finite-difference time-domain algorithm curved surfaces E-plane horn antenna far-field patterns

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A novel contour-path finite-difference time-domain (CPFDTD) algorithm for modeling objects with curved surfaces

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Microwave and Optical Technology Letters 2000年第4期28卷

作者： Yikyu Min Byungsoo Kil Sangseol Lee Division of Electronic and Computer Engineering Hanyang University Seoul 133-791 Korea

A novel CPFDTD algorithm for modeling smooth curved surfaces is presented. This scheme subdivides electric fields on the distorted grid into the extended contour field, the nondistorted field, and the quasiavailable field to avoid the collinear borrowing approximation. Several earlier methods are applied to the E -plane sectoral horn antenna to obtain far-field patterns. To show the validity and applicability of our method, computed far-field patterns are compared with measured values. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 28: 285–287, 2001.

关键词： finite-difference time-domain algorithm curved surfaces E-plane horn antenna far-field patterns

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Combining standard with optimised split-step finite-difference time-domain methods for the study of graphene configurations

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IET SCIENCE MEASUREMENT & TECHNOLOGY 2019年第8期13卷 1150-1157页

作者： Amanatiadis, Stamatios A. Zygiridis, Theodoros T. Kantartzis, Nikolaos, V Aristotle Univ Thessaloniki Dept Elect & Comp Engn Thessaloniki 54124 Greece Ormylia Fdn Art Diag Ctr Ormylia 63071 Greece Univ Western Macedonia Dept Elect & Comp Engn Kozani 50131 Greece

In this study, the authors propose a hybrid computational model for the reliable simulation of electromagnetic-wave phenomena emerging in graphene structures, which incorporates two variations of an unconditionally-stable finite-difference time-domain algorithm. The new approach features: (a) a dispersive model that relies on the auxiliary differential equation technique and takes into consideration the graphene's surface conductivity, and (b) a modified discretisation algorithm implementing error-optimised spatial approximations, which is appropriate for graphene-free mesh nodes. The resulting update equations are devoid of time-step restrictions, thus formulating a suitable and useful computational framework for the investigation of contemporary graphene-based problems, which commonly call for densely-sampled grids and/or prolonged simulations. After theoretically assessing the fundamental features of the proposed algorithm, the propagation properties of surface waves on graphene are extracted numerically and compared with analytical estimations, so that computational validation is provided. In addition, a realistic surface-wave coupler configuration is simulated and its main characteristics are extracted accurately, exemplifying the method's robustness on more complex setups.

关键词： differential equations graphene finite difference time-domain analysis surface conductivity electromagnetic wave propagation graphene structures finite-difference time-domain algorithm dispersive model auxiliary differential equation technique modified discretisation algorithm error-optimised spatial approximations graphene-free mesh nodes resulting update equations time-step restrictions useful computational framework contemporary graphene-based problems computational validation optimised split-step finite-difference time-domain graphene configurations hybrid computational model reliable simulation electromagnetic wave phenomena surface wave propagation properties surface conductivity realistic surface wave coupler configuration C

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Electromagnetic coupling between arbitrarily bent wires and scatterers analysed by a hybrid MoMTD/FDTD approach

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IEE PROCEEDINGS-MICROWAVES ANTENNAS AND PROPAGATION 2000年第4期147卷 261-266页

作者： Cerri, G Chiarandini, S Russo, P Schiavoni, A Univ Ancona Dipartimento Elettron & Automat I-60131 Ancona Italy Ctr Studi & Lab Telecomun SpA CSELT I-10140 Turin Italy

The payer presents a new hybrid method for efficiently studying the coupling between an antenna and an inhomogeneous penetrable object, lying in the near field region of the source. It is based on the combination of the marching on in time version of the method of moment (MoMTD), and the finite-difference in time-domain (FDTD) algorithm. The use of the equivalence principle leads to the treatment of the original complex problem as the interaction of two simpler subproblems, each of them approached differently. The hybrid method is validated by comparing our results obtained for significant strong coupling cases with data computed by other numerical techniques and with experimental values.

关键词： Antenna theory finite difference time-domain analysis method of moments near field region electromagnetic coupling Electromagnetic wave propagation FDTD algorithm inhomogeneous penetrable object hybrid MoMTD/FDTD approach bent wires marching on in time version antenna electromagnetic wave scattering finite-difference time-domain algorithm antenna theory subproblems Other numerical methods scatterers equivalence principle

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Simple pictograph for displaying complex field data in TEM cell tissue sample

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ELECTRONICS LETTERS 2002年第8期38卷 359-360页

作者： Lim, HB Cook, GG Barker, AT Coulton, LA Univ Sheffield Dept Elect & Elect Engn Radar & Commun Grp Sheffield S1 3JD S Yorkshire England Royal Hallamshire Hosp Dept Med Phys & Clin Engn Sheffield S10 2JF S Yorkshire England Univ Sheffield No Gen Hosp Div Clin Sci Sheffield S5 7AU S Yorkshire England

A simple diagram is described Cor displaying complex field data calculated using an original finite-difference time-domain algorithm. This polar plot is used to display field properties within a culture medium placed in a transverse electro-magnetic (TEM) cell, and shows the presence of an elliptically polarised exposure field with reactive phasing, arising from a plane wave incident field. The pictograph aids in comprehending this field behaviour, which may be relevant to any biological effects.

关键词： complex field data display finite-difference time-domain algorithm FDTD algorithm biological effects of fields diagrams culture medium elliptically polarised exposure field reactive phasing electromagnetic fields biological tissue samples finite difference time-domain analysis biological effects Numerical approximation and analysis dosimetry experiments field properties polar plot Radiation protection and dosimetry Radiation dosimetry in medical physics Biological effects of radiations transverse electromagnetic cell Other numerical methods plane wave incident field biological techniques dosimetry pictograph Biophysical instrumentation and techniques

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Angular independent frequency selective surfaces for interference control in indoor wireless environments

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ELECTRONICS LETTERS 2012年第2期48卷 61-U22页

作者： Taylor, P. S. Austin, A. C. M. Parker, E. A. Neve, M. J. Batchelor, J. C. Yiin, J. T. -P. Leung, M. Rowe, G. B. Williamson, A. G. Sowerby, K. W. Univ Kent Sch Engn & Digital Arts Canterbury CT2 7NT Kent England Univ Auckland Dept Elect & Comp Engn Auckland 1142 New Zealand

A study of electromagnetic wave propagation in buildings using a finite-difference time-domain algorithm has demonstrated that waves are incident on walls over a wide range of angles. If wall mounted frequency selective shielding is desired, it is argued that this behaviour requires shielding solutions that are angle insensitive. A simple single-layer annular ring frequency selective surface (which is relatively economic to fabricate) is shown to offer adequate angular stability of the transmission response, and is thus suitable for electromagnetic interference control in indoor wireless environments.

关键词： finite-difference time-domain algorithm Electromagnetic compatibility and interference angular independent frequency selective surfaces single-layer annular ring frequency selective surface electromagnetic interference control Electromagnetic wave propagation transmission response electromagnetic interference indoor radio wall mounted frequency selective shielding electromagnetic wave propagation indoor wireless environment frequency selective surfaces Radio links and equipment

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Modelling of infrared bandpass filters using three-dimensional FDTD method

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ELECTRONICS LETTERS 2005年第16期41卷 914-915页

作者： Qiang, R Chen, J Zhao, T Wang, S Ruchhoeft, P Morgan, M Univ Houston Dept Elect & Comp Engn Houston TX 77204 USA EDTEK Inc Kent WA 98032 USA

A three-dimensional finite-difference time-domain algorithm was developed to model the spectral behaviour of infrared bandpass filters consisting of plus-shaped openings in a thin gold film. This algorithm incorporates the Lorentz-Drude model to accurately describe the frequency-dependent permittivity of the gold at IR frequencies. The computed transmission spectrum is compared with measured data and excellent agreement between the two results is observed.

关键词： finite-difference time-domain algorithm 3D FDTD method frequency selective surfaces optical filters frequency-dependent permittivity spectral behaviour finite difference time-domain analysis Numerical approximation and analysis infrared bandpass filters spectral analysis Optical coatings and filters gold metallic thin films band-pass filters Other numerical methods thin gold film transmission spectrum Lorentz-Drude model IR frequencies Spectral and other filters

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GPR antenna simulations and optimizations in time domain 4

GPR antenna simulations and optimizations in time domain

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4th International Conference on Antenna Theory and Techniques

作者： Ligthart, LP Yarovoy, AG Kirana, AY Delft Univ Technol Int Res Ctr Telecommun Transmiss NL-2628 CD Delft Netherlands

ISBN: (纸本)0780378814

The development and optimization of transient antennas for Ground Penetrating Radar would be difficult without numerical simulations of their performance. To this end the FDTD algorithm should be considered as a useful and powerful tool for transient antenna analysis. As an example of such analysis we describe simulations of the dielectric wedge antenna. Good agreement between theoretical predictions and experimental results was observed. Some of the antenna characteristics (like the radial component of the electric field in the near zone, the radiated waveform and the antenna footprint in different grounds) cannot be measured easily, so the correct theoretical (numerical) model is essential for their determination. The numerical model of the antenna can also be used for optimization of the antenna. As an example of such optimization we present a design of the shield for the dielectrically embedded dipole antenna.

关键词： transient antennas finite-difference time-domain algorithm Ground Penetrating Radar

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Analysis of finite periodic structure by FDTD and SOC technique

Analysis of finite periodic structure by FDTD and SOC techni...

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Asia-Pacific Microwave Conference

作者： Ye, Z. B. Chen, R. S. Yang, Y. Nanjing Univ Sci & Technol Dept Commun Engn Nanjing 210094 Peoples R China

ISBN: (纸本)078039433X

In this paper, the application of the finite-difference time-domain (FDTD) algorithm combined with the short-open calibration SOC technique to three-dimensional finite periodic structure is presented. We can get the scattering parameters of the whole periodic structure through analyzing only one cell of it. So the combination of the SOC technique and FDTD for finite periodic structures makes the calculation much faster and much more accurate. Results for finite periodic structure are well compared with the conventional FDTD method.

关键词： S-parameters calibration finite difference time-domain analysis microstrip discontinuities periodic structures 3D finite periodic structure finite-difference time-domain algorithm scattering parameters short-open calibration technique

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