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21st International Conference on Electromagnetics in Advanced Applications (ICEAA)

作者： Kawaguchi, Hideki Muroran Inst Technol Dept Elect & Informat Engn Muroran Hokkaido Japan

ISBN: (纸本)9781728105635

This paper considers speed-up of a calculation of an absorbing boundary condition (ABC) of the finite-difference time-domain (FDTD) method based on a time-domain surface integral equation. The most popular ABC of the FDTD method, the perfectly matched layer (PML), is still required to be modified for its accuracy in cases of near field and large incident angle to ABC. The ABC based on the time-domain surface integral equation is free from such confinements of the ABC location and incident angle. On the other hand, it is known that extremely heavy computation cost is required for the time-domain surface integral. In this work, it is attempted to reduce the computation cost of the surface integral equation to use spherical harmonics expression for harmonic Green's function in the surface integral equation.

关键词： finite-difference time-domain method absorbing boundary condition perfectly matched layer time-domain surface integral equation surface equivalent theorem electric and magnetic surface charge and current densities spherical harmonics expression multi-pole expansion

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GROUND PENETRATING RADAR DATA INTERPRETATION USING ELECTROMAGNETIC FIELD ANALYSIS FOR SEA ICE THICKNESS MEASUREMENT

GROUND PENETRATING RADAR DATA INTERPRETATION USING ELECTROMA...

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ISPRS Technical Commission III WG III/2, 10 Joint Workshop on Multidisciplinary Remote Sensing for Environmental Monitoring

作者： Matsumoto, M. Yoshimura, M. Naoki, K. Cho, K. Wakabayashi, H. PASCO CORP Meguro Ku 2-8-10 Higashiyama Tokyo Japan Univ Tokyo Ctr Spatial Informat Sci Meguro Ku Tokyo Japan Tokai Univ Shibuya Ku 2-28-4 Tomigaya Tokyo Japan Nihon Univ 1 Nakagawara Koriyama Fukushima Japan

Observation of sea ice thickness by remote sensing is one of key issues to understand an effect of global warming. However, ground truth must be necessary to discuss this kind of approach. Although there are several methods to acquire ice thickness, Ground Penetrating Radar (GPR) can be good solution because it can discriminate snow-ice and ice-sea water interface thanks to comparative higher spatial resolution than the other methods. In this paper, we carried out GPR measurement in brackish lake and an electromagnetic field analysis in order to interpret the GPR data. The simulation model was assumed considering the actual snow and ice thickness acquired in field measurement. From the simulation results, although it seems difficult to identify the reflection at snow and ice interface due to a thin layer thickness and a low dielectric constant, snow and ice thickness may be estimated by using multiple reflection components.

关键词： Sea ice thickness measurement Ground truth Ground Penetrating Radar Brackish lake finite-difference time-domain method Dielectric constant Multiple reflection

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Effect of horizontal sound-absorptive strips inside closed rooms

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ACOUSTICAL SCIENCE AND TECHNOLOGY 2020年第5期41卷 709-719页

作者： Asakura, Takumi Yashima, Wataru Satoh, Fumiaki Tokyo Univ Sci 2641 Yamazaki Noda Chiba 2780022 Japan Chiba Inst Technol 2-17-1 Tsudanuma Narashino Chiba 2750016 Japan

The sound absorption characteristics obtained with horizontally arranged sound-absorptive strips on walls were evaluated by objective measure based on the acoustical indices determined from the impulse responses calculated by finite-difference time-domain simulation. The subjective effect of the horizontal sound-absorptive strips (HSSs) was also investigated by subjective measure based on Scheffe's paired comparison method. The results of the numerical case study confirmed that the frequency characteristics of the acoustic indices of rooms with the HSSs significantly changed under the influence of the relative positional relationship between the source and receiving points and the arrangement height of the strips. Through a subjective evaluation experiment, the differences in the absorption effect of various types of settings of the strips on the reverberation inside rooms were also clarified.

关键词： Sound-absorptive strip finite-difference time-domain method Room-acoustic indices Scheffe's paired comparison method

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Transfer of Information using Surface-Plasmon-Polariton Waves 19

Transfer of Information using Surface-Plasmon-Polariton Wave...

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Conference on Optical Interconnects XIX

作者： Agrahari, Rajan Lakhtakia, Akhlesh Jain, Pradip K. Indian Inst Technol BHU Dept Elect Engn Varanasi 221005 Uttar Pradesh India Penn State Univ NanoMM Nanoengn Metamat Grp Dept Engn Sci & Mech University Pk PA 16802 USA Indian Inst Technol BHU Mat Architecture Ctr Varanasi 221005 Uttar Pradesh India Natl Inst Technol Dept Elect & Commun Patna 800005 Bihar India

ISBN: (数字)9781510624917

ISBN: (纸本)9781510624917

The limitations of electronic and optical interconnects inside a semiconductor chip could be overcome by the used of plasmonic-polaritonic interconnects whereby information is carried by surface-plasmon-polariton (SPP) waves guided by planar metal/dielectric interface. Investigating the propagation of a pulse-modulated carrier SPP wave when the metal is either abruptly terminated or bent and the dielectric material is air, we have found that SPP-wave-based interconnects can be effective conduits of information.

关键词： Plasmonic communication surface-plasmon-polariton wave finite-difference time-domain method

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A Stochastic FDTD method for Rectangular Objects with Geometric Uncertainties 8

A Stochastic FDTD Method for Rectangular Objects with Geomet...

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8th International Conference on Modern Circuit and System Technologies (MOCAST)

作者： Salis, Christos Kantartzis, Nikolaos Zygiridis, Theodoros Univ Western Macedonia Dept Informat & Telecommun Engn Kozani 50131 Greece Aristotle Univ Thessaloniki Dept Elect & Comp Engn Thessaloniki 54124 Greece

ISBN: (纸本)9781728111841

The uncertainties present in various dielectric materials may have an effect on the properties of the electromagnetic components. Deterministic schemes are unable to capture the statistics of the examined quantities and as a result, reliable outcomes cannot be extracted. In this paper, we present a novel two-dimensional (2D) finite-difference time domain (FDTD) method, that manages to calculate the statistics of the involved fields in a single simulation. The proposed algorithm is a variation of the Stochastic FDTD method and is suitable for assessing random media uncertainties, as well as to estimate the variation in the width and height of a random rectangular dielectric. Numerical results indicate the validity of our scheme compared with the Monte Carlo approach.

关键词： finite-difference time-domain method Monte Carlo Non-uniform grids Stochastic FDTD Uncertainty problems

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Performance analysis of vertically cascaded pentacle micro-optical ring resonator as optical filters with four output bus waveguides

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OPTICAL ENGINEERING 2018年第11期57卷

作者： Chatterjee, Binshati Mandal, Sanjoy Indian Inst Technol Indian Sch Mines Dhanbad Bihar India Indian Inst Technol ISM Elect Engn Dept Dhanbad Bihar India

Modeling and performance analysis of vertically cascaded pentacle micro-optical ring resonator (VCPMORR) with single input and four output bus waveguides is presented. Overall transmittance of the proposed VCPMORR is determined in Z-domain for each output bus waveguide by practicing delay line signal processing approach and Mason's gain formula. Frequency response analysis of the proposed model is carried out using MATLAB software. Free spectral range (FSR), group delay, and dispersion are enumerated as performance parameters of the proposed model. The detailed design of its waveguide is carried out by employing finite-difference time-domain (FDTD) method. Electric field propagation through the rings and the wave-guides is also studied by FDTD. This method proposes an approach to design the numerous coupled ring resonator structures. This configuration provides more communication channels due to its wide FSR with zero crosstalk at four output buses. Hence, this coupled ring resonator structure will be very useful in optical communication systems as an optical add-drop filter. (C) 2018 Society of Photo-Optical Instrumentation Engineers (SPIE)

关键词： delay line signal processing Mason's gain formula free spectral range group delay dispersion finite-difference time-domain method

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Toward Wave-based Sound Synthesis for Computer Animation

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ACM TRANSACTIONS ON GRAPHICS 2018年第4期37卷 1-16页

作者： Wang, Jui-Hsien Qu, Ante Langlois, Timothy R. James, Doug L. Stanford Univ Stanford CA 94305 USA Adobe Res Seattle WA USA

We explore an integrated approach to sound generation that supports a wide variety of physics-based simulation models and computer-animated phenomena. Targeting high-quality offline sound synthesis, we seek to resolve animation-driven sound radiation with near-field scattering and diffraction effects. The core of our approach is a sharp-interface finite-difference time-domain (FDTD) wavesolver, with a series of supporting algorithms to handle rapidly deforming and vibrating embedded interfaces arising in physics-based animation sound. Once the solver rasterizes these interfaces, it must evaluate acceleration boundary conditions (BCs) that involve model- and phenomena-specific computations. We introduce acoustic shaders as a mechanism to abstract away these complexities, and describe a variety of implementations for computer animation: near-rigid objects with ringing and acceleration noise, deformable (finite element) models such as thin shells, bubble-based water, and virtual characters. Since time-domain wave synthesis is expensive, we only simulate pressure waves in a small region about each sound source, then estimate a far-field pressure signal. To further improve scalability beyond multi-threading, we propose a fully time-parallel sound synthesis method that is demonstrated on commodity cloud computing resources. In addition to presenting results for multiple animation phenomena (water, rigid, shells, kinematic deformers, etc.) we also propose 3D automatic dialogue replacement (3DADR) for virtual characters so that pre-recorded dialogue can include character movement, and near-field shadowing and scattering sound effects.

关键词： Computer animation sound synthesis finite-difference time-domain method acoustics

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Morphologies and optical and electrical properties of InGaN/GaN micro-square array light-emitting diode chips

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APPLIED OPTICS 2018年第11期57卷 2835-2840页

作者： Han, Dan Ma, Shufang Jia, Zhigang Liu, Peizhi Jia, Wei Shang, Lin Zhai, Guangmei Xu, Bingshe Taiyuan Univ Technol Minist Educ Key Lab Interface Sci & Engn Adv Mat Taiyuan 030024 Shanxi Peoples R China Taiyuan Univ Technol Res Ctr Adv Mat Sci & Technol Taiyuan 030024 Shanxi Peoples R China Shaanxi Univ Sci & Technol Inst Atom & Mol Sci Xian 710021 Shaanxi Peoples R China

InGaN/GaN micro-square array light-emitting diode (LED) chips (micro-chips) have been prepared via the focused ion beam (FIB) etching technique, which can not only reduce ohmic contact degradation but also control the aspect ratio precisely in three-dimensional (3D) structure LED (3D-LED) device fabrication. The effects of FIB beam current and micro-square array depth on morphologies and optical and electrical properties of the micro-chips have been studied. Our results show that sidewall surface morphology and optical and electrical properties of the micro-chips degrade with increased beam current. After potassium hydroxide etching with different times, an optimal current-voltage and luminescence performance can be obtained. Combining the results of cathodoluminescence mappings and light output-current characteristics, the light extraction efficiency of the micro-chips is reduced as FIB etch depth increases. The mechanisms of micro-square depth on light extraction have been revealed by 3D finite difference time domain. (C) 2018 Optical Society of America

关键词： Aluminum oxide finite-difference time-domain method Light extraction Optical properties Scanning electron microscopy Visible light communications

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Double and triple-wavelength plasmonic demultiplexers based on improved circular nanodisk resonators

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OPTICAL ENGINEERING 2018年第10期57卷

作者： Khani, Shiva Danaie, Mohammad Rezaei, Pejman Semnan Univ Elect & Comp Engn Fac Semnan Iran

Plasmonic demultiplexers using improved circular nanodisk resonators (CNRs) and metal-insulator-metal waveguides have been designed. The proposed structures use air and silver as insulator and metal layers, respectively. The relative permittivity of silver has been characterized by Drude, Palik, and Drude-Lorentz models in our finite-difference time-domain simulations. To obtain demultiplexers, first two filters based on improved CNRs are designed. One of the most outstanding features of a CNR is that the resonance wavelength can be tuned by changing its radius. It is shown that increasing the CNRs radii for the single-mode bandpass filter increases the resonance wavelength, linearly. Accordingly, double and triple-wavelength demultiplexers (DeMuxes) have been proposed for the wavelength range of 600 to 2000 nm. Due to their small area, the proposed demultiplexers can be applied in integrated optical circuits for optical communication purposes. (C) 2018 Society of Photo-Optical Instrumentation Engineers (SPIE)

关键词： plasmonic demultiplexer metal-insulator-metal waveguide circular nanodisk resonator Drude-Lorentz model finite-difference time-domain method

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Protective Effect of Shield Wires Against Direct Lightning Flashes to Buried Cables

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IEEE TRANSACTIONS ON POWER DELIVERY 2018年第4期33卷 1628-1635页

作者： Tanaka, Hiroki Baba, Yoshihiro Barbosa, Celio Fonseca Tsuboi, Toshihiro Okabe, Shigemitsu Doshisha Univ Dept Elect Engn Kyoto 6100321 Japan R&D Ctr Telecommun CPqD BR-13086902 Campinas SP Brazil Tokyo Elect Power Co Ltd Tokyo Elect Power Co Res Inst Yokohama Kanagawa 2308510 Japan

The protective effect of a shield wire against direct lightning flashes to a buried power cable has been clarified in this paper. The finite-difference time-domain (FDTD) method is used in the investigation. The FDTD model considers a 1-km-long insulated cable protected by a shield wire, and a lightning strike right above them. The model has been validated by comparing its results with experimental results available in the literature. The computed results show that the presence of the shield wire can effectively prevent the cable from being directly struck by the lightning flash. The voltage across the cable insulation at the striking point depends on the ground resistivity (the higher the resistivity, the higher the voltage), but this dependence is not linear. It is also shown that the soil surface ionization is relevant to the current delivered to the shield wire and to the voltage developed across the cable insulation. On the other hand, the soil ionization around the shield wire has negligible effects. The intrinsic resistance of the shield wire does not influence significantly the peak voltage across the cable insulation, but it influences its duration (the higher the intrinsic resistance, the longer the voltage duration).

关键词： Cable insulation electromagnetic shielding finite-difference time-domain method lightning protection

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