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A VIE-based algebraic domain decomposition for analyzing electromagnetic scattering from inhomogeneous isotropy/anisotropy dielectric objects
摘要： A VIE-based domain decomposition method (DDM) is proposed for analyzing EM scattering from inhomogeneous electrically large dielectric objects. The volume integral equation (VIE) still uses tetrahedra to model the entire body and uses the SWG basis functions to expand the equivalent electric ?ux density. This new DDM is established by dividing the unknowns on the whole electrically large body into groups, serving as subdomains. Through necessary symmetry treatment of standard MoM impedance matrix, the DDM using subdomain-decoupling technology can be combined with the VIE model to reduce memory requirement. Actually, this is an algebraic DDM, not a geometric DDM. In other words, it has no requirement of physical location of basis functions belonging to the same subdomain. This decoupling procedure is completely eliminating the coupling impact of the primary subdomain with the rest of the dielectric body, until every subdomain is independent with each other. In this work, when solving ultimate decoupled impedance subdomain matrix, the LU decomposition process for solving interpolating coef?cients of multiple right sides is accelerated by GPU parallel technology to signi?cantly decrease CPU time. In brief, this paper ?rst time combines the algebraic DDM with the conventional VIE model (including both isotropy and anisotropy VIE model) to signi?cantly decrease the requirement of memory. At last, a few representative numerical examples are provided to demonstrate validity, ef?ciency and stability of the new method.
关键词： MoM,volume integral equation,domain decomposition
更新于2025-09-23 15:23:52
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[IEEE 2018 International Conference on Radar (RADAR) - Brisbane, Australia (2018.8.27-2018.8.31)] 2018 International Conference on Radar (RADAR) - Radar Cross Section of Modified Target Using Gaussian Beam Methods: Experimental Validation
摘要： The aim of this paper is to study the Radar Cross Section (RCS) of modified radar targets (plate with notch) using Gaussian Beam techniques. The Gaussian methods used in this work are Gaussian Beam Summation (GBS) and Gaussian Beam Launching (GBL). We establish the theoretical formulation of the GBS and GBL techniques and analyze the influence of the main Gaussian beam parameters on the variation of the scattered field. Then, we present the simulations of RCS. The numerical results are compared with PO, MoM methods, and also with experimental measurements performed in the anechoic chamber at Lab-STICC (ENSTA Bretagne).
关键词： Radar Cross Section (RCS),Physical Theory of Diffraction (PTD),Physical Optic (PO),Gaussian Beam Summation (GBS),Gaussian Beam Launching(GBL),Method of Moment (MoM)
更新于2025-09-23 15:22:29
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COMPUTATIONAL ASPECTS OF 2D-QUASI-PERIODIC-GREEN-FUNCTION COMPUTATIONS FOR SCATTERING BY DIELECTRIC OBJECTS VIA SURFACE INTEGRAL EQUATIONS
摘要： We describe a surface integral-equation (SIE) method suitable for computation of electromagnetic ?elds scattered by 2D-periodic high-permittivity and plasmonic scatterers. The method makes use of fast evaluation of the 2D-quasi-periodic Green function (2D-QPGF) and its gradient using a tabulation technique in combination with tri-linear interpolation. In particular we present a very e?cient technique to create the look-up tables for the 2D-QPGF and its gradient where we use to our advantage that it is very e?ective to simultaneously compute the QPGF and its gradient, and to simultaneously compute these values for the case in which the role of source and observation point are interchanged. We use the Ewald representation of the 2D-QPGF and its gradient to construct the tables with pre-computed values. Usually the expressions for the Ewald representation of the 2D-QPGF and its gradient are presented in terms of the complex complementary error function but here we give the expressions in terms of the Faddeeva function enabling e?cient use of the dedicated algorithms to compute the Faddeeva function. Expressions are given for both lossy and lossless medium parameters and it is shown that the expression for the lossless case can be evaluated twice as fast as the expression for the lossy case. Two case studies are presented to validate the proposed method and to show that the time required for computing the method of moments (MoM) integrals that require evaluation of the 2D-QPGF becomes comparable to the time required for computing the MoM integrals that require evaluation of the aperiodic Green function.
关键词： Faddeeva function,surface integral-equation (SIE) method,Ewald representation,method of moments (MoM),2D-quasi-periodic Green function (2D-QPGF)
更新于2025-09-23 15:19:57
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The Fast Solver for Calculating the Scattered Fields from the Multiscale Scatterers
摘要： In this work, the efficient methods for calculating the scattered fields from the electrically large scatterers and multiscale scatterers are discussed. The MoM-PO method is introduced to obtain the scattered fields from the multiscale scatterers. Due to the highly oscillatory behavior of the physical optics (PO) integrals, the numerical contour deformation technique is proposed to calculate the PO scattered fields. The z buffer acceleration technique based on GPU is adopted to distinguish between the lit and shadow regions of the surfaces. Numerical examples from the electrically large and multiscale scatterers are provided to benchmark the efficiency of the proposed method.
关键词： Physical optics,parallel PO method,MoM-PO,z buffer,the TD-NSDP method,the NSDP method
更新于2025-09-19 17:15:36
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Nanoplasmonics - Fundamentals and Applications || Impedance Matching Analysis of Cylindrical Plasmonic Nanoantennas Fed by Optical Transmission Lines
摘要： An impedance matching analysis of two plasmonic nanocircuits connected to cylindrical nanoantennas is presented. In the first case, a bifilar optical transmission line (OTL) with finite length is connected between two nanodipoles, where one is illuminated by an optically focused Gaussian beam (receiving dipole) and the other radiates energy received from the OTL (emitting dipole). In the second case, the OTL is fed by a voltage source on one side and connected to a dipole‐loop composed antenna on the other side. These circuits are analysed electromagnetically by the linear method of moments (MoM) with equivalent surface impedance of conductors. Some results are compared using the finite element method. The results show the impedance matching characteristics of the circuits as a function of their geometries and the broadband response of the second circuit due the broadband dipole‐loop antenna.
关键词： broadband nanoantennas,cylindrical nanoantennas,method of moments (MoM),impedance matching,plasmonic circuits
更新于2025-09-19 17:13:59
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Plasmonic Nano-antenna Optimization Using Characteristic Mode Analysis
摘要： Plasmonic nano-antennas are typically designed with RF-inspired rigorous parametric optimization processes that lack proper physical insights. In this study, we demonstrate a systematic optimization approach for nano-antennas based on characteristic mode analysis (CMA). A complex geometry, designated as split-ring two-wire antenna (SRA), is selected and optimized using the CMA technique. CMA identifies the dominant modes of the structure at the frequency of interest as well as explains the dependency of the modes on the structure’s shape, size and material properties. These insights from CMA have been used in the present study to efficiently optimize SRA shape, size, and material which yield more than 700 % near-field intensity enhancement (NFIE) at the desired operating frequency. This proposed CMA based optimization method can be adapted easily for many other nano-antenna applications, facilitating the development of improved nano-structures.
关键词： Split-ring Two-wire Antenna (SRA),Method of Moments (MOM),Plasmonic,Nano-structures / Nano-antennas,Near Field Intensity Enhancement (NFIE),Surface Integral Equation (SIE),Characteristic Mode Analysis (CMA)
更新于2025-09-11 14:15:04
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Handbook of Graphene || Modelling of Graphene Nanoribbons Antenna Based on MoM‐GEC Method to Enhance Nanocommunications in Terahertz Range
摘要： In this chapter, we present an electromagnetic modelling formulation of graphene nanoribbon antenna based on moments method combined to the generalized equivalent circuit method (MoM-GEC). The electrical properties of graphene are introduced in the mathematical formulation via a quantum mechanical conductivity deduced from the Kubo formalism. The antenna structure is shielded in a rectangular waveguide with electric boundary walls. Next, the global antenna structure is modelled by an electric equivalent circuit to investigate the antenna parameters. It is proved that, graphene nanoribbon-based antenna presents similar performances as well as conventional one, hence allowing to work at terahertz frequencies range. The high input impedance of a single graphene nanoribbon antenna causes an impedance mismatch problem, which requires the use of an antenna array. So, the coupling phenomena have been well studied in order to optimize the antenna response. Obtained numerical results show that the antenna resonant frequency is very sensitive to the variation of the graphene chemical potential. This leads to a reconfigurable antenna by a simple control of bias voltage. On the other hand, it is showed that, at terahertz frequencies, graphene nanoribbon antenna array allows to enhance the far field communication for short distances, which is beneficial for nanocommunications.
关键词： antenna array,nanocommunications,dynamic conductivity,terahertz range,nanoantenna,MoM-GEC method,Graphene nanoribbon
更新于2025-09-11 14:15:04
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[IEEE 2018 XXIIIrd International Seminar/Workshop on Direct and Inverse Problems of Electromagnetic and Acoustic Wave Theory (DIPED) - Tbilisi, Georgia (2018.9.24-2018.9.27)] 2018 XXIIIrd International Seminar/Workshop on Direct and Inverse Problems of Electromagnetic and Acoustic Wave Theory (DIPED) - MoM Solution to Scattering Problem on Multi-Region Composite Structures with Various Type Material Junctions
摘要： This paper develops a MoM-based full-wave solution to the scattering problem on arbitrary multi-region composite structure with various type junctions between dielectric and conducting regions. A special attention is paid to the treatment of basis functions (BF) on material junctions. In contrast to existing works, the standard RWG BF are supposed to be used and grouped according to the boundary conditions on contiguous interfaces. The proposed approach has been validated by comparison of the simulated results with those obtained by discontinuous Galerkin time domain (DGTD) method.
关键词： Basis functions,method of moments (MoM),material junctions,numerical simulations,composite structures
更新于2025-09-11 14:15:04
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Simulation of Circular Cylindrical Metasurfaces using GSTC-MoM
摘要： Modeling of circular cylindrical metasurfaces using Method of Moments (MoM) based on Generalized Sheet Transition Conditions (GSTCs) is presented. GSTCs are used to link the integral equations for fields on the inner and outer contour of the circular cylindrical metasurface. The GSTC-MoM is validated by two examples: (1) anisotropic, gyrotropic metasurface capable of two field transformations, (2) non-gyrotropic metasurface capable of transforming field generated by an infinite electric line source at origin to field generated by a displaced electric line source. The formulations presented here can be used as a platform for deriving GSTC-MoM for 3D spherical and conformal metasurfaces.
关键词： GSTC,Integral Equation,Metasurface,MoM,Electromagnetic discontinuity,Boundary condition,Susceptibility,Bianisotropy,Cylindrical
更新于2025-09-10 09:29:36