- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Fast modeling of electromagnetic scattering from 2D electrically large PEC objects using the complex line source type Green's function
摘要： This study introduces an alternative approach to the numerical solution of two-dimensional (2D) electromagnetic scattering problems by a numerical method of moments (MoM). The real source position vector is replaced by a complex quantity, then Green’s function generates a complex source point beam, therefore the interactions between the far zone elements in the impedance matrix are neglected, except the basis functions near to the edges, strongly localizing the impedance matrix. The memory storage increases with the number of edges, but for a fixed number of the edges, it is linearly proportional with N, i.e. O(N). Consequently, the overall running time can be drastically reduced and the far zone scattering pattern and the near field can be found. The proposed procedure is first explained for the single perfectly electrically conducting (PEC) strip geometry, then extended to the scattering by 2D PEC objects with closed polygonal cross-sections. Numerical results are presented for a strip and a square cylinder in both polarizations. The relative errors are also compared with the standard MoM.
关键词： computational electromagnetics,radar cross section,Electromagnetic scattering
更新于2025-09-23 15:23:52
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Coupling finite elements and auxiliary sources for Maxwell's equations
摘要： The Multiple Multipole Program is a Trefftz method approximating the electromagnetic field in a domain filled with a homogeneous linear medium. MMP can easily handle unbounded domains; yet, it cannot accommodate inhomogeneous or nonlinear materials, situations well within the scope of the standard finite element method. We propose to couple FEM and MMP to model Maxwell's equations for materials with spatially varying properties in an unbounded domain. In some bounded parts of the domain, we use Nédélec's first family of curl-conforming elements; in the unbounded complement, multipole expansions. Several approaches are developed to couple both discretizations across the common interface: 1. Least-squares–based coupling using techniques from PDE-constrained optimization. 2. Multifield variational formulation in the spirit of mortar finite element methods. 3. Discontinuous Galerkin coupling between the FEM mesh and the single-entity MMP subdomain. 4. Coupling by tangential components traces. We study the convergence of these approaches in a series of numerical experiments.
关键词： Method of Auxiliary Sources,Multiple Multipole Program,Finite Element Method,Computational electromagnetics,Trefftz method
更新于2025-09-23 15:22:29
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H-MATRIX ARITHMETIC FOR FAST DIRECT AND ITERATIVE METHOD OF MOMENT SOLUTION OF SURFACE-VOLUME-SURFACE EFIE FOR 3-D RADIATION PROBLEMS
摘要： Hierarchical (H-) matrix based fast direct and iterative algorithms are presented for acceleration of the Method of Moment (MoM) solution of the Surface-Volume-Surface Electric Field Integral Equation (SVS-EFIE) formulated for scattering and radiation problems on homogeneous dielectric objects. As the SVS-EFIE features the product of the integral operator mapping the tangential equivalent electric current on the surface of the scatterer to the volume polarization current and the integral operator mapping the volume polarization current to the tangential component of the scattered electric field, its MoM discretization produces the product of non-square matrices. Formation of the non-square H-matrices for the MoM discretized integral operators is described. The algorithms for arithmetics pertinent to the product of the non-square H-matrices are explained. The memory and CPU time complexity scaling of the required H-matrix operations are analyzed in details and verified numerically. The numerical validation of the proposed algorithm is provided for both the low-loss dielectric objects as well as for the high-loss biological tissues found in the bioelectromagnetics applications. The numerical experiments demonstrate a significant reduction of memory usage and a considerable speedup for CPU time compared to na?ve MoM, thus, enabling solution of the large-scale scattering and radiation problems with the SVS-EFIE.
关键词： computational electromagnetics,Method of Moments,SVS-EFIE,fast algorithms,bioelectromagnetics,H-matrix
更新于2025-09-23 15:22:29
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Plasma and Plasmonics || 9 Numerical Methods for Electromagnetics
摘要： In this chapter, we will discuss some of the basic numerical methods that can be used to perform computer simulations of Maxwell’s equations in various conditions. Computational electromagnetics is a very broad field with too many different methods available for different situations. But we will only give a brief introduction to this topic in this book and encourage the reader to refer to other sources [31] for more details.
关键词： Maxwell’s equations,Electromagnetics,Numerical Methods,Computational Electromagnetics
更新于2025-09-23 15:19:57
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Metamaterials, Anapoles and Flying Donuts
摘要： Heat-assisted magnetic recording (HAMR) allows for data writing in hard disks beyond 1 Tb/in2 areal density, by temporarily heating the area of a single bit to its Curie temperature. The metallic optical antenna or near-?eld transducer (NFT), used to apply the nanoscale heating to the media, may self-heat by several hundreds of degrees. With the NFT reaching such extreme temperatures, demonstrations of HAMR technology experience write-head lifetimes that are orders of magnitude less than that required for a commercial product. Hence, heating of the NFT is of upmost importance. In this paper, we ?rst derive fundamental limits on the temperature ratio NFT/Media to drive NFT design choices for low-temperature operation. Next, we employ inverse electromagnetic design software, which solves for unexpected geometries of the NFT and waveguide. We present computationally generated designs for the waveguide feeding the NFT that offer a 50% reduction in NFT self-heating (～220 °C) compared with typical industry designs.
关键词： HAMR,optimization,plasmonics,nanophotonics,near-?eld transducer (NFT),inverse problem,heat-assisted magnetic recording thermal,computational electromagnetics,hard disks,gradient methods,management,Adjoint method,optical antenna
更新于2025-09-19 17:13:59
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[IEEE ESSDERC 2019 - 49th European Solid-State Device Research Conference (ESSDERC) - Cracow, Poland (2019.9.23-2019.9.26)] ESSDERC 2019 - 49th European Solid-State Device Research Conference (ESSDERC) - Suspended Antenna-Coupled Nanothermocouple Array for Long-Wave Infrared Detection
摘要： Heat-assisted magnetic recording (HAMR) allows for data writing in hard disks beyond 1 Tb/in2 areal density, by temporarily heating the area of a single bit to its Curie temperature. The metallic optical antenna or near-field transducer (NFT), used to apply the nanoscale heating to the media, may self-heat by several hundreds of degrees. With the NFT reaching such extreme temperatures, demonstrations of HAMR technology experience write-head lifetimes that are orders of magnitude less than that required for a commercial product. Hence, heating of the NFT is of upmost importance. In this paper, we first derive fundamental limits on the temperature ratio NFT/Media to drive NFT design choices for low-temperature operation. Next, we employ inverse electromagnetic design software, which solves for unexpected geometries of the NFT and waveguide. We present computationally generated designs for the waveguide feeding the NFT that offer a 50% reduction in NFT self-heating (～220 °C) compared with typical industry designs.
关键词： optical antenna,Adjoint method,computational electromagnetics,heat-assisted magnetic recording,near-field transducer (NFT),management,thermal,nanophotonics,plasmonics,gradient methods,inverse problem,optimization,hard disks
更新于2025-09-19 17:13:59
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A Review on the Application of Integral Equation‐Based Computational Methods to Scattering Problems in Plasmonics
摘要： Many computational methods have been developed and used for modeling, understanding, and tailoring extreme optical effects at the nanoscale. Among them, this review focuses on the integral equation-based methods: within the local response limit, a potential-based boundary integral equation (BIE) formalism and a field-based volume integral equation (VIE) formalism; within the nonlocal hydrodynamic model, a potential-based BIE formalism. These formalisms are derived from macroscopic electrodynamics (together with appropriate constitutive relations). The derivations are based on three pillars: the Green function, the field relation(s) (for the VIE formalism, the incident—scattered—total field relation; for the BIE formalism, the interface conditions connecting the fields at two sides of the interface), and the field equivalence principle (for the VIE formalism, the volume equivalence principle; for the BIE formalism, the Huygens principle). By applying the method of moments (MoM) algorithm, the derived integral equations are converted into matrix equations, with possible problems in the implementation being discussed. Levels of solutions, including the eigenmode and natural mode solutions, and group representation theory are introduced as powerful post-processing steps. Many examples are shown to demonstrate the effectiveness of the reviewed algorithms.
关键词： nonlocal hydrodynamic model,computational electromagnetics,boundary integral equations,plasmonics,volume integral equations
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE BiCMOS and Compound semiconductor Integrated Circuits and Technology Symposium (BCICTS) - Nashville, TN, USA (2019.11.3-2019.11.6)] 2019 IEEE BiCMOS and Compound semiconductor Integrated Circuits and Technology Symposium (BCICTS) - Coherent Transceiver for High Speed Optical Communications: Opportunities and Challenges
摘要： Conformal (or body-?tted) electromagnetic particle-in-cell (EM-PIC) numerical solution schemes are reviewed. Included is a chronological history of relevant particle physics algorithms often employed in these conformal simulations. Brief mathematical descriptions of particle-tracking algorithms and current weighting schemes are provided, along with a brief summary of major time-dependent electromagnetic solution methods. Several research areas are also highlighted for recommended future development of new conformal EM-PIC methods.
关键词： Computational electromagnetics,conformal mesh,reviews,plasma simulation,particle in cell (PIC)
更新于2025-09-16 10:30:52
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Complex- <i>k</i> modes of plasmonic chain waveguides
摘要： Nanoparticle chain waveguide based on negative-epsilon material is investigated through a generic 3D finite-element Bloch-mode solver which derives complex propagation constant (k). Our study starts from waveguides made of non-dispersive material, which not only singles out ‘waveguide dispersion’ but also motivates search of new materials to achieve guidance at unconventional wavelengths. Performances of gold or silver chain waveguides are then evaluated; a concise comparison of these two types of chain waveguides has been previously missing. Beyond these singly-plasmonic chain waveguides, we examine a hetero-plasmonic chain system with interlacing gold and silver particles, inspired by a recent proposal; the claimed enhanced energy transfer between gold particles appears to be a one-sided view of its hybridized waveguiding behavior—energy transfer between silver particles worsens. Enabled by the versatile numerical method, we also discuss effects of inter-particle spacing, background medium, and presence of a substrate. Our extensive analyses show that the general route for reducing propagation loss of e.g. a gold chain waveguide is to lower chain-mode frequency with a proper geometry (e.g. smaller particle spacing) and background material setting (e.g. high-permittivity background or even foreign nanoparticles). In addition, the possibility of building mid-infrared chain waveguides using doped silicon is commented based on numerical simulation.
关键词： plasmonics,periodic structure,computational electromagnetics,waveguide,photonic band structure,finite-element simulation
更新于2025-09-11 14:15:04
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Real-Time Modeling of Forward-Looking Synthetic Aperture Ground Penetrating Radar Scattering From Rough Terrain
摘要： Ground penetrating radar (GPR) is a viable tool for fast and high fidelity detection of concealed explosive threats. The radar effectiveness is limited by scattering from rough terrain which considerably obscures the buried target response. To calculate the rough ground scattering, a 3-D full-wave algorithm such as finite-difference frequency-domain (FDFD) method is required but is often prohibitive for multiple frames when the GPR antennas are distant from the target region. This paper presents a real-time 3-D modeling of a moving platform forward-looking GPR scattering from rough terrain located at great electrical distances from the GPR antenna. For a synthetic aperture, the computational domain of the focal region is reduced to a very small subset of the entire observed volume, and the surface clutter is computed via a mere multiplication of a precomputed impulse response matrix of the rough ground with the matrix characterizing the GPR transmitting signal. For a vehicle-mounted GPR detection system, this results in a significant reduction of complexity and saving of computation resources. The effectiveness of the algorithm is evaluated through an implementation of 3-D Monte Carlo simulation for various rough surface parameters. Our developed model compares well with the direct FDFD results, and can be used for lossy and frequency-dispersive soils.
关键词： ground penetrating radar (GPR),Computational electromagnetics (EMs),rough surface scattering,subsurface detection
更新于2025-09-09 09:28:46