- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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[IEEE 2019 IEEE High Power Diode Lasers and Systems Conference (HPD) - Coventry, United Kingdom (2019.10.9-2019.10.10)] 2019 IEEE High Power Diode Lasers and Systems Conference (HPD) - Applications of thermoreflectance imaging to high-power diode laser diagnostics
摘要： A time-domain electric ?eld volume integral equation (TD-EFVIE) solver is proposed for characterizing transient electromagnetic wave interactions on high-contrast dielectric scatterers. The TD-EFVIE is discretized using the Schaubert–Wilton–Glisson (SWG) and approximate prolate spherical wave (APSW) functions in space and time, respectively. The resulting system of equations cannot be solved by a straightforward application of the marching on-in-time (MOT) scheme since the two-sided APSW interpolation functions require the knowledge of unknown “future” ?eld samples during time marching. Causality of the MOT scheme is restored using an extrapolation technique that predicts the future samples from known “past” ones. Unlike the extrapolation techniques developed for MOT schemes that are used in solving time-domain surface integral equations, this scheme trains the extrapolation coef?cients using samples of exponentials with exponents on the complex frequency plane. This increases the stability of the MOT-TD-EFVIE solver signi?cantly, since the temporal behavior of decaying and oscillating electromagnetic modes induced inside the scatterers is very accurately taken into account by this new extrapolation scheme. Numerical results demonstrate that the proposed MOT solver maintains its stability even when applied to analyzing wave interactions on high-contrast scatterers.
关键词： extrapolation,electric ?eld volume integral equation (EFVIE),transient analysis,time-domain analysis,Band-limited interpolation,marching on-in-time (MOT) method
更新于2025-09-23 15:19:57
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[IEEE 2019 8th International Conference on Renewable Energy Research and Applications (ICRERA) - Brasov, Romania (2019.11.3-2019.11.6)] 2019 8th International Conference on Renewable Energy Research and Applications (ICRERA) - Effects of Price Developments on Photovoltaic Panel to Inverter Power Ratios
摘要： A time-domain electric ?eld volume integral equation (TD-EFVIE) solver is proposed for characterizing transient electromagnetic wave interactions on high-contrast dielectric scatterers. The TD-EFVIE is discretized using the Schaubert–Wilton–Glisson (SWG) and approximate prolate spherical wave (APSW) functions in space and time, respectively. The resulting system of equations cannot be solved by a straightforward application of the marching on-in-time (MOT) scheme since the two-sided APSW interpolation functions require the knowledge of unknown “future” ?eld samples during time marching. Causality of the MOT scheme is restored using an extrapolation technique that predicts the future samples from known “past” ones. Unlike the extrapolation techniques developed for MOT schemes that are used in solving time-domain surface integral equations, this scheme trains the extrapolation coef?cients using samples of exponentials with exponents on the complex frequency plane. This increases the stability of the MOT-TD-EFVIE solver signi?cantly, since the temporal behavior of decaying and oscillating electromagnetic modes induced inside the scatterers is very accurately taken into account by this new extrapolation scheme. Numerical results demonstrate that the proposed MOT solver maintains its stability even when applied to analyzing wave interactions on high-contrast scatterers.
关键词： transient analysis,Band-limited interpolation,time-domain analysis,extrapolation,marching on-in-time (MOT) method,electric ?eld volume integral equation (EFVIE)
更新于2025-09-23 15:19:57
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Electromagnetic Physical Numerical Modeling of a GaN Distributed Transferred Electron Devicea??Based Planar Waveguide THz Oscillator
摘要： The radio frequency (RF) operation of a planar waveguide THz oscillator based on the distributed transferred electron device (DTED) is theoretically investigated by means of 2-D time-domain numerical physical modeling based on the self-consistent solution of the Maxwell and free electron energy-momentum macroscopic transport equations.
关键词： circuit design analysis,distributed transferred electron device (DTED),2-D time-domain electromagnetic physical numerical modeling,planar waveguide THz oscillator
更新于2025-09-23 15:19:57
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[IEEE 2019 Photonics & Electromagnetics Research Symposium - Fall (PIERS - Fall) - Xiamen, China (2019.12.17-2019.12.20)] 2019 Photonics & Electromagnetics Research Symposium - Fall (PIERS - Fall) - The Full-space Bessel Beam Modulator Based on Pancharatnam-Berry Metasurface
摘要： Time-domain channel characterization (TCC) for de-embedding of an asymmetric fixture is introduced. Two design criteria for the design of a 2x-thru are proposed. Error sensitivity regarding a small error in the S-parameters of the 1x-fixture is analyzed with an insertion loss error-coefficient and a return loss error-coefficient. The TCC procedure, including proposed design criteria and error sensitivity, is also introduced to reduce the error in the TCC application. Three different 2x-thru structures are investigated for the verification of the two proposed design criteria and analyzed for error sensitivity. Test fixtures on a printed circuit boards are fabricated for the experimental verification.
关键词： return loss error-coefficient (RLEC),design criteria,De-embedding,error-coefficient,time-domain channel characterization (TCC),insertion loss error-coefficient (ILEC),error sensitivity
更新于2025-09-23 15:19:57
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[IEEE 2019 Antenna Measurement Techniques Association Symposium (AMTA) - San Diego, CA, USA (2019.10.6-2019.10.11)] 2019 Antenna Measurement Techniques Association Symposium (AMTA) - A Low-Cost Multicopter Based Near-Field Antenna Measurement System Employing Software Defined Radio and 6-D Laser Metrology
摘要： With the purpose of avoiding very fine mesh cells in the proximity of a thin wire, the modified telegrapher’s equations (MTEs) are employed to describe the thin wire voltage and current distributions, which consequently results in reduced number of unknowns and augmented Courant–Friedrichs–Lewy (CFL) number. As hyperbolic systems, both the MTEs and the Maxwell’s equations are solved by the discontinuous Galerkin time-domain (DGTD) method. In realistic situations, the thin wires could be either driven or loaded by circuit networks. The thin wire–circuit interface performs as a boundary condition for the thin wire solver, where the thin wire voltage and current used for the incoming flux evaluation involved in the DGTD-analyzed MTEs are not available. To obtain this voltage and current, an auxiliary current flowing through the thin wire–circuit interface is introduced at each interface. Corresponding auxiliary equations derived from the invariable property of characteristic variable for hyperbolic systems are developed and solved together with the circuit equations established by the modified nodal analysis (MNA) modality. Furthermore, in order to characterize the field and thin wire interactions, a weighted electric field and a volume current density are added into the MTEs and Maxwell–Ampere’s law equation, respectively. To validate the proposed algorithm, three representative examples are presented.
关键词： thin wire–circuit boundary,Characteristic variable,discontinuous Galerkin time-domain (DGTD) method,modified telegrapher’s equation (MTE),hyperbolic system,modified nodal analysis (MNA)
更新于2025-09-23 15:19:57
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A Tunable Terahertz Metamaterial Absorber Composed of Hourglass-Shaped Graphene Arrays
摘要： In this paper, we demonstrate a tunable periodic hourglass‐shaped graphene arrays absorber in the infrared (IR) and terahertz (THz) frequency bands. The effects of graphene geometric parameters, chemical potentials, periods, and incident angles on the pure absorption characteristics are studied by using the Finite Difference Time Domain (FDTD) method. In addition, this paper also analyzes the pure absorption characteristics of bilayer graphene arrays. The simulation results show that the maximum absorption reaches 38.2% for the monolayer graphene structure. Furthermore, comparing the bilayer graphene structure with the monolayer structure under the same conditions shows that the bilayer structure has a tunable dual‐band selective absorption effect and has a higher maximum absorption of 41.7%. Moreover, it was found that there are dual‐band tunable absorption peaks at 21.6 μm and 36.3 μm with the maximum absorption of 41.7% and 11%. The proposed structure is a convenient method which could be used in the design of graphene‐based optoelectronic devices, biosensors, and environmental monitors.
关键词： surface plasmon resonance,metamaterial absorber,graphene,finite difference time domain
更新于2025-09-23 15:19:57
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[IEEE 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Rome, Italy (2019.6.17-2019.6.20)] 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Brillouin Optical Time Domain Analysis with Wavelength-locked Low-noise Pump-probe Laser Scheme
摘要： A doubly resonant short cavity Brillouin ring-laser actively stabilized with a wavelength locking system are employed as a low-RIN pump-probe source for Brillouin optical time-domain analysis (BOTDA) sensing. The developed high-stability narrow-linewidth laser scheme is compared to a long-cavity ring laser, showing the potential for enhanced temperature-strain resolutions.
关键词： wavelength-locked,temperature-strain resolutions,BOTDA,low-noise pump-probe laser,Brillouin Optical Time Domain Analysis
更新于2025-09-23 15:19:57
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Application of Genetic Algorithm for More Efficient Multi-Layer Thickness Optimization in Solar Cells
摘要： Thin-?lm solar cells are predominately designed similar to a stacked structure. Optimizing the layer thicknesses in this stack structure is crucial to extract the best ef?ciency of the solar cell. The commonplace method used in optimization simulations, such as for optimizing the optical spacer layers’ thicknesses, is the parameter sweep. Our simulation study shows that the implementation of a meta-heuristic method like the genetic algorithm results in a signi?cantly faster and accurate search method when compared to the brute-force parameter sweep method in both single and multi-layer optimization. While other sweep methods can also outperform the brute-force method, they do not consistently exhibit 100% accuracy in the optimized results like our genetic algorithm. We have used a well-studied P3HT-based structure to test our algorithm. Our best-case scenario was observed to use 60.84% fewer simulations than the brute-force method.
关键词： optical modelling,?nite difference time domain,genetic algorithm,solar cell optimization
更新于2025-09-23 15:19:57
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Thermal expansion of α-nitrogen ice in terahertz spectroscopy
摘要： The volumetric thermal expansion coef?cient of a-nitrogen (N2) ice is calculated for temperatures between 10 and 25 K using its terahertz transmission data and a phonon model. The observed dip in terahertz transmission around 1.45 THz is modeled as phonon absorption based on an intermolecular potential which is sum of the Lennard-Jones potential and quadrupole–quadrupole interaction term. Using this model and our experimental data, the lattice parameters of a-N2 ice were obtained.
关键词： Thermal expansion,Terahertz,Time-domain spectroscopy,a-Nitrogen ice
更新于2025-09-23 15:19:57
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Numerical Investigation of the Equalization Enhanced Phase Noise Penalty for M-Quadrature Amplitude Modulation Formats in Short-Haul Few-Mode Fiber Transmission Systems with Time-Domain Equalization
摘要： The equalization enhanced phase noise (EEPN), caused by the interaction of the chromatic dispersion (CD) with the phase noise of the local oscillator (LO), has been extensively studied for single-mode optical communication systems. Few-mode fiber (FMF) transmission systems introduce a new channel impairment, the differential mode delay (DMD), which also creates EEPN and hence limits the maximum transmission distance of those systems. In this work, we numerically investigate the optical signal to noise ratio (OSNR) penalties caused by the EEPN in a 3-mode FMF transmission system at 25 GBd for quadrature phase-shift keying (QPSK), 16-quadrature amplitude modulation (QAM), 32-QAM and 64-QAM modulation formats when using the blind phase search (BPS) carrier phase recovery (CPR) algorithm, which has been demonstrated to be both robust and suitable for optical communication systems. Our numerical study assumes a short-span of FMF, modeled in the weakly-coupled regime, and includes two cases; the use of ideal mode-selective de/multiplexers at both ends of the FMF span (model A), and the use of ideal non-mode-selective de/multiplexers (model B). The results show that the EEPN has almost no effect in model A. However, EEPN produces a severe penalty in model B with the onset of the OSNR degradation starting for a DMD spread of the impulse response of about 100 symbols for all modulation formats investigated. The distribution ratio of the amount of phase noise between the transmitter and receiver lasers is also assessed for model B and we confirm that the degradation is mainly due to the phase noise of the LO.
关键词： equalization enhanced phase noise,mode-division multiplexing,few-mode fiber optical communication systems,time-domain MIMO equalization
更新于2025-09-19 17:15:36