- 标题
- 摘要
- 关键词
- 实验方案
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B-scan wave outline analysis in numerical modeling of ground-penetrating radar response from layered rough interfaces
摘要： Imaging of rough interfaces in a layered structure requires full understanding of the characteristics of their ground penetrating radar (GPR) echoes. In this study, a finite-difference time-domain computational model using a uniaxial perfectly matched layer boundary for GPR demining of layered rough interfaces is constructed. On the basis of this model, the numerical results of B-scan echoes from two-layered and three-layered rough interfaces with different degrees of roughness are obtained and compared with the profiles of corresponding rough surfaces. These results and comparisons highlight the relationship between the B-scan wave outlines and the profile of the layered rough interfaces. The effect of roughness of the interface on the B-scan echoes are analyzed, and the influence of the upper rough surface profile on the shape of the B-scan wave outline from the lower rough surface is discussed.
关键词： layered rough interfaces demining,finite-difference time-domain method (FDTD),ground penetrating radar (GPR),echo characteristic analysis
更新于2025-09-23 15:22:29
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One-Step Leapfrog HIE-FDTD for Drude Media
摘要： A one-step leapfrog hybrid implicit–explicit finite-difference time-domain (HIE-FDTD) method is developed for Drude dispersive media. The Drude media is modeled through a current source characterized by a semi-implicit auxiliary differential equation. The stability condition is the same as that of conventional leapfrog HIE-FDTD and is determined by the grid cell size along only one direction. The proposed method is used to efficiently investigate the properties of surface plasmon polaritons propagating along a one-atom-thick graphene sheet in low terahertz band with a very fine grid.
关键词： Drude dispersive media,graphene,hybrid implicit–explicit finite-difference time-domain method,one-step leapfrog,stability
更新于2025-09-23 15:22:29
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[IEEE 2019 International Applied Computational Electromagnetics Society Symposium - China (ACES) - Nanjing, China (2019.8.8-2019.8.11)] 2019 International Applied Computational Electromagnetics Society Symposium - China (ACES) - Double-Ridge Waveguide Mode Analysis based on FDTD-SVD Method
摘要： In this paper,hybrid finite-difference time-domain method(FDTD) and singular value decomposition(SVD),denoted by FDTD-SVD,is applied to analyze the double-ridge waveguide dominant mode. Double-ridge waveguide (WRD) without fillets and WRD with small fillets are analyzed.The simulation results show WRD without fillets can achieve a single-mode operation of 10TE from 35GHz to 112 GHz. For WRD with small fillets, its single-mode operation frequency band is 35-116GHz.These results are almost consistent with the detailed parametric study result(38-120GHz)based on Ansys HFSS, which proves that the FDTD-SVD method is simple and more effective. In addition, the transmission performance of WRD can be improved by adding fillets and enlarging the radius of fillets.
关键词： mode analysis,singular value decomposition(SVD),finite-difference time-domain method(FDTD),double-ridge waveguide(WRD)
更新于2025-09-23 15:21:01
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Strong Exciton-Plasmon Coupling and Hybridization of Organic-Inorganic Exciton-Polaritons in Plasmonic Nanocavity <sup>*</sup>
摘要： We investigate strong exciton-plasmon coupling and plasmon-mediated hybridization between the Frenkel (F) and Wannier–Mott (WM) excitons of an organic-inorganic hybrid system consisting of a silver ring separated from a monolayer WS2 by J-aggregates. The extinction spectra of the hybrid system calculated by employing the coupled oscillator model are consistent with the results simulated by the finite-difference time-domain method. The calculation results show that strong couplings among F excitons, WM excitons, and localized surface plasmon resonances (LSPRs) lead to the appearance of three plexciton branches in the extinction spectra. The weighting efficiencies of the F exciton, WM exciton and LSPR modes in three plexciton branches are used to analyze the exciton-polaritons in the system. Furthermore, the strong coupling between two different excitons and LSPRs is manipulated by tuning F or WM exciton resonances.
关键词： coupled oscillator model,finite-difference time-domain method,localized surface plasmon resonances,plasmonic nanocavity,exciton-plasmon coupling,Frenkel excitons,organic-inorganic hybrid system,Wannier–Mott excitons
更新于2025-09-23 15:21:01
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Design and analysis of a plasmonic demultiplexer based on band-stop filters using double-nanodisk-shaped resonators
摘要： In this paper, a two-channel plasmonic wavelength demultiplexer (PWDM) based on band-stop filters (BSF) using double-nanodisk-shaped resonators is proposed. The structure is numerically simulated using finite difference time domain method. First, a BSF is considered for modeling which supports three modes. Then, the effect of various structural parameters of the proposed PWDM is studied on the transmission properties in detail. The results show that the transmission properties of our PWDM are highly dependent on geometric parameters. The proposed structure provides a single-mode spectrum on each of the output ports with a maximum quality factor as high as 105 (FWHM = 7.7 nm). To this end, we illustrate that the concerning published research in this field, the significant privilege of our proposed PWDM structure is in terms of its good transmission efficiency, lowest FWHM and highest quality factor. Hence, such an arrangement is easy to fabricate and it has the potential for use in all-optical ultra-compact circuits and devices.
关键词： Metal–insulator–metal waveguide,Plasmonic demultiplexer,Nanodisk resonator,Plasmonic filter,Surface plasmon polariton,Finite difference time-domain method
更新于2025-09-16 10:30:52
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[IEEE 2018 Australasian Universities Power Engineering Conference (AUPEC) - Auckland, New Zealand (2018.11.27-2018.11.30)] 2018 Australasian Universities Power Engineering Conference (AUPEC) - Nano-structured GaAs Solar Cell Design, Simulation and Analysis for Conversion Efficiency Improvement
摘要： This paper discusses nano-structured GaAs solar cell design and analysis for conversion efficiency improvement by increasing the light transmission and absorption, reducing the light reflection. The focus of this research is to construct different type of nano-grating shaped GaAs solar cells with various nano-grating heights and pitches, to compare the simulation results and find a suitable nano-structure that can provide higher conversion efficiency. Finite difference time domain (FDTD) simulation tool is used to simulate and calculate transmission and absorption for different nano-grating shapes, such as, parabolic, triangular, trapezoidal and rectangular. Based on the simulation results, it has been confirmed that the light reflection of parabolic shaped nano-grating structures is higher than triangular nano-grating structures, but it is lower than rectangular and trapezoidal shaped nano-grating structures. Moreover, the simulation results confirmed that the light transmission of parabolic shaped nano-grating structures is about 62.3% having a 200-nm grating height and an 810-nm grating pitch, which is about 22% higher than the rectangular (i.e., flat) type substrates.
关键词： Finite-difference time-domain method,transmission,GaAs solar cells,and absorption,Nano-grating structure,Light reflection,Conversion efficiency,Solar or renewable energy
更新于2025-09-16 10:30:52
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Tunable plasmonic absorber in THz-band range based on graphene “arrow” shaped metamaterial
摘要： A tunable selective absorber consisting of a periodic “arrow” shaped graphene array that operates in the far infrared and terahertz range is proposed. It is achieved by depositing a set of graphene “arrow” shaped ribbon on a SiO2 dielectric spacer layer. The absorption characteristics of the structure are investigated by the Finite Difference Time Domain (FDTD) method. The results show that the maximum pure absorption rate at the resonant wavelength increases from 1.09% corresponding to Fermi energy level 0.2 eV to 12.76% corresponding to 0.8 eV, which is improved by nearly 12 times. Moreover, the relaxation time is increased from 0.1 ps to 1.0 ps with the other parameters are unchanged, and the maximum value of the pure graphene absorption peak increases from 1.62% to 11.55%. Moreover, the resonance wavelengths of the absorber possess angle insensitivity, nevertheless the absorption peak intensity is sensitive to the angle of incidence. In addition, this paper also compares the double-symmetric “arrow” shaped structure on the basis of this structure. The absorption spectrum of the structure shows a double peak phenomenon, which can achieve the purpose of selective absorption. The research results have certain guiding significance and important reference value for the design of next–generation graphene-based perfect terahertz absorbers, and the design can be applied to the fields of label-free biomedical sensing, photodetectors and photonic devices.
关键词： Absorber,Finite Difference Time Domain method,Surface plasmon,Graphene,Metamaterial
更新于2025-09-12 10:27:22
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Time-domain Formulation of a Multi-layer Plane Circuit Coupled with Lumped-parameter Circuits using Maxwell Equations
摘要： We calculate electromagnetic phenomena in the multi-layer plane circuit starting from the Maxwell equations. We present a numerical method of potential and current density in two-dimensional conductors, where their time developments are treated as phenomena of wave propagation. We treat the plane conductors by dividing them into small finite-volume elements, similar to the case of the partial element equivalent circuit method, and the transport equations are then solved by the finite-difference time-domain method. Furthermore, we develop a calculation method for the boundary in a multi-layer plane by applying the method we have used in multi-transmission lines. We formulate the boundary conditions of a multi-layer plane coupled with lumped-parameter circuits and introduce an algorithm to reduce calculation costs that are largely associated with the two-dimensional extension from the multi-transmission-line case. We perform calculations of the wave propagation of potential, current density, and charge density in the time domain for a simple plane circuit. these calculations are presented as supplementary materials of the present paper.
关键词： wave propagation,multi-layer plane circuit,electromagnetic phenomena,lumped-parameter circuits,potential and current density,numerical method,finite-difference time-domain method,Maxwell equations
更新于2025-09-11 14:15:04
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Time-Division Parallel FDTD Algorithm
摘要： We propose a novel and efficient algorithm to parallelize the finite-difference time-domain method, where the observation period is divided into an arbitrary number of subsections, whose computation is distributed to corresponding computer nodes. The proposed algorithm roughly reduces the computational time to an n-th fraction of the conventional algorithm, where n is the number of nodes for parallel computing, thus verifying its efficiency improvement.
关键词： finite-difference complex-frequency-domain method,fast inverse Laplace transform,finite-difference time-domain method,time-division parallel algorithm
更新于2025-09-10 09:29:36
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Hourglass nonlinear photonic crystal cavity for ultra-fast all-optical switching
摘要： In this paper, a new design of an ultra fast all optical switch based on a new photonic crystal cavity combined with Kerr effect is proposed and its performance is studied. Numerical methods such as plane wave expansion (PWE) and finite difference time domain (FDTD) are used to perform simulations and study the optical properties of the proposed switch. Switching from ON to OFF status occurred when the resonant wavelength is shifted due to Kerr effect. The simulation results show that switch has a high-speed response of ~15ps and since it has an ultra-small size of 273.24 μm2, it has a potential to be used in integrated optical-circuits.
关键词： All-optical switching,Finite-Difference Time-Domain method,Optical Kerr effect,Photonic crystal cavity
更新于2025-09-09 09:28:46