- 标题
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- 实验方案
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Panda Resonator Structure to Generate Four-Wave Mixing by Nonlinear Effect
摘要： Finite-difference time domain (FDTD) simulation has been used for modeling of nonlinear optical interaction in a modified microring resonator as Panda structure. By proposing the Panda structure which has been modeled using both silicon and material (Chi2) with nonlinear effect, generation of four-wave mixing is feasible. Due to the nonlinear interaction between the two input waves as pump and signal within the microring resonators the results show the generation of three picks including the pump, signal and converted wave. In the case, if the silicon has been utilized as the core waveguide, the resonance interferences occur, where the high Qfactor of the resonance frequencies was obtained as 3.87 × 103 in the drop port outputs. Compared to silicon material, the nonlinear material shows a better power transferring performances. In the results showing the four-wave mixing, the converted wave has a lower power than the signal and pump.
关键词： nonlinear effect.,Panda structure,FDTD,Four-wave mixing
更新于2025-09-23 15:21:21
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RESEARCH ON MINIMUM ENERGY EXCITED TO PLASMA COATING FOR REDUCING RADAR CROSS SECTION OF TARGET
摘要： To reduce the radar cross section (RCS) of a target, plasma coating on perfectly electric conducting plate is studied in this paper. Nonuniform helium plasma produced by a minitype solid rocket engine is with collisional and unmagnetized. Energy excited for generating helium plasma is investigated. Based on the collisional, unmagnetized, and cold plasma model, backscattering RCS is computed by using ?nite-di?erence time-domain method. Principle of RCS reduction is explained. To ?nd minimum input energy while RCS reduced, relationship between input power and RCS reduction is discussed, and numerical optimization is also implemented. We can identify optimal parameters and choose the best electron density pro?le under condition of given input power level.
关键词： Radar Cross Section (RCS),Plasma Coating,Input Power,Electron Density,Finite-Difference Time-Domain (FDTD) Method
更新于2025-09-23 15:21:21
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[IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Generation of light beams by electron beam excited surface plasmons
摘要： Manipulation of Smith-Purcell radiation (SPR) by electron-bunch excitation of localized surface plasmon (LSP) of gold (Au) disc arrays on Au substrate is investigated by FDTD simulation. When the wavelength of LSP mode is within the SPR emission band, SPR is locked and enhanced at the LSP wavelength. The emission angle of LSP-locked SPR still follows the wavelength-angle relation of traditional SPR. Furthermore, both the emission wavelength and angle increase as the radius and height of Au disc increase.
关键词： FDTD simulation,Smith-Purcell radiation (SPR),localized surface plasmon (LSP)
更新于2025-09-23 15:21:21
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Design of a Wide Ranging Highly Sensitive Pressure Sensor Based on Two-Dimensional Photonic Crystals
摘要： A highly sensitive pressure sensor operating over a wide pressure range based on two-dimensional photonic crystals having a Mach-Zehnder interferometer structure has been developed. The plane wave expansion method (PWE) is used to determine the device operating wavelength range. The finite difference time domain method (FDTD) is used to calculate the device characteristic parameters such as the resonant frequency, the power transmission, and the sensitivity. The present sensor has two wide frequency ranges, a high sensitivity to refractive index changes and the highest detectable sensitivity pressure so far reported in the literature, that is, 25.06 nm/GPa. The present device has high and constant transmission power all over the entire pressure range 0 to 10 GPa. This is of practical importance since the constraints imposed on the sensing system (the light source and the photodetector) are the same.
关键词： Power transmission,Sensitivity,Mach-Zehnder interferometer,Pressure sensor,2-D photonic crystals,FDTD
更新于2025-09-23 15:21:21
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Material distributive topology design of UWB antenna using parallel computation of improved BPSO with FDTD
摘要： In this article, the material distributive topology-based design optimization of ultra-wide band (UWB) antenna is proposed by using improved binary particle swarm optimization (BPSO) with finite difference time domain (FDTD) method. In the improved BPSO implementation, the velocity of each particle is calculated based on complete set of bits of particle position vector. The V-shaped transfer function is employed to transform all real values of velocities to values in the interval [0,1]. The fitness function of all the particles in BPSO algorithm are computed parallely by using FDTD simulation. The usage of FDTD and the parallel computation helps in analyzing the broadband frequency characteristics of the antenna with a single simulation run. The return loss of the optimized UWB antenna obtained from FDTD, Computer Simulation Technology (CST) simulation and practical measurement are in good agreement and show good impedance matching.
关键词： UWB antenna,finite difference time domain (FDTD) method,topology optimization,Binary particle swarm optimization (BPSO)
更新于2025-09-23 15:21:21
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AIP Conference Proceedings [Author(s) INTERNATIONAL CONFERENCE OF NUMERICAL ANALYSIS AND APPLIED MATHEMATICS (ICNAAM 2017) - Thessaloniki, Greece (25–30 September 2017)] - Additive, multiplicative and iterative splitting methods for Maxwell equations: Algorithms and applications
摘要： We are motivated to optimise splitting methods for Maxwell’s equations. The methods are based on additive, multiplicative and iterative splitting approaches and embed an optimised computation of the Maxwell operators. We decompose Maxwell’s equations into sub-operators and apply the di?erent splitting methods. We obtain numerical bene?ts, while we apply iterative splitting approaches and optimise the computations of the sub-operators. Standard methods, such as additive and multiplicative methods, are more e?ective in fast results, which iterative approaches could reduce iteratively the errors. We present some initial numerical examples for the optimised splitting approaches.
关键词： FDTD scheme,Iterative and exponential splitting
更新于2025-09-23 15:21:21
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Enhanced optical efficiency and color purity for organic light-emitting diodes by finely optimizing parameters of nanoscale low-refractive index grid
摘要： To extract the confined waveguided light in organic light-emitting diodes (OLEDs), inserting a low refractive index (RI) periodic structure between the anode and organic layer has been widely investigated as a promising technology. However, the periodic-structure-based light extraction applied inside devices has been shown to severely distort spectrum and affect EL characteristics. In this study, a simple light extraction technology using periodic low-RI nanodot array (NDA) as internal light extraction layer has been demonstrated. The NDA was fabricated simply via laser interference lithography (LIL). The structural parameters of periodic pattern, distance, and height were easily controlled by the LIL process. From computational analysis using finite-difference time-domain (FDTD) method, the NDA with 300 nm pitch and 0.3 coverage ratio per unit cell with 60 nm height showed the highest enhancement with spectral-distortion-minimized characteristics. Through both computational and experimental systematic analysis on the structural parameters of low-RI NDA-embedded OLEDs, highly efficient OLEDs have been fabricated. Finally, as representative indicators, hexagonal and rectangular positioned NDA-embedded OLEDs showed highly improved external quantum efficiencies of 2.44 (+29.55%) and 2.77 (+57.38%), respectively. Furthermore, the disadvantage originating from the nanoscale surface roughness on the transparent conductive oxide was minimized.
关键词： organic light-emitting diodes,nanodot array,FDTD simulation,laser interference lithography,light extraction,low refractive index
更新于2025-09-23 15:21:01
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[IEEE 2019 International Conference on Communication and Electronics Systems (ICCES) - Coimbatore, India (2019.7.17-2019.7.19)] 2019 International Conference on Communication and Electronics Systems (ICCES) - Design and performance analysis of WDM optical Communication system with EDFA-DCF and FBG for dispersion compensation using $8\mathrm{x}5$ Gbps data rate
摘要： The way in which electromagnetic ?elds are transmitted and received by ground penetrating radar (GPR) antennas is crucial to the performance of GPR systems. Simple antennas have been characterized by analyzing their radiation patterns and directivity. However, there have been limited studies that combine real GPR antennas with realistic environments, which is essential to capture the complex interactions between the antenna and surroundings. We have investigated the radiation characteristics and sensitivity of a GPR antenna in a range of lossy dielectric environments using both physical measurements and a three-dimensional (3-D) ?nite-difference time-domain (FDTD) model. Experimental data were from measured responses of a target positioned at intervals on the circumference of a circle surrounding the H-plane of the antenna. A series of oil-in-water emulsions as well as tap water were used to simulate homogeneous materials with different permittivities and with complex conductivities. Numerical radiation patterns were created utilizing a detailed 3-D FDTD model of the antenna. Good correlation was shown between the experimental results and modeled data with respect to the strength of the main lobe within the critical angle window. However, there are discrepancies in the strength of main lobe at shallow angles. In all the dielectrics, the main lobes are generally broad due to the near-?eld observation distance but, as expected, become narrower with increasing permittivity. These results provide con?dence for further use of the FDTD antenna model to investigate scenarios such as larger observation distances and heterogeneous environments that are dif?cult to study experimentally.
关键词： electromagnetic modeling,Antenna measurements,?nite-difference time-domain (FDTD),antenna radiation patterns,broadband antennas
更新于2025-09-23 15:21:01
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[Institution of Engineering and Technology 8th Renewable Power Generation Conference (RPG 2019) - Shanghai, China (24-25 Oct. 2019)] 8th Renewable Power Generation Conference (RPG 2019) - The Method of Grid Disturbance Test for Very Large Capacity Photovoltaic Inverter Based on Hardware-In-Loop Simulation Platform
摘要： A three-dimensional (3-D) finite-difference time-domain (FDTD) algorithm is used in order to simulate ground penetrating radar (GPR) for landmine detection. Two bowtie GPR transducers are chosen for the simulations and two widely employed antipersonnel (AP) landmines, namely PMA-1 and PMN are used. The validity of the modeled antennas and landmines is tested through a comparison between numerical and laboratory measurements. The modeled AP landmines are buried in a realistically simulated soil. The geometrical characteristics of soil’s inhomogeneity are modeled using fractal correlated noise, which gives rise to Gaussian semivariograms often encountered in the field. Fractals are also employed in order to simulate the roughness of the soil’s surface. A frequency-dependent complex electrical permittivity model is used for the dielectric properties of the soil, which relates both the velocity and the attenuation of the electromagnetic waves with the soil’s bulk density, sand particles density, clay fraction, sand fraction, and volumetric water fraction. Debye functions are employed to simulate this complex electrical permittivity. Background features like vegetation and water puddles are also included in the models and it is shown that they can affect the performance of GPR at frequencies used for landmine detection (0.5–3 GHz). It is envisaged that this modeling framework would be useful as a testbed for developing novel GPR signal processing and interpretations procedures and some preliminary results from using it in such a way are presented.
关键词： rough surface,GPR,water puddles,modeling,FDTD,antipersonnel (AP) landmines,roots,dispersive,fractals,Antennas,bowtie,GprMax,grass,vegetation
更新于2025-09-23 15:21:01
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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