Article
Engineering, Electrical & Electronic
Li-Ming Zhang, A-Li Deng
Summary: This article proposes a hybrid discretization scheme for solving the volume integral equation (VIE) for electromagnetic scattering from dielectric objects using SWG-Edge basis functions. The method is shown to be more efficient for multi-boundary problems compared to traditional SWG basis functions.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2021)
Article
Engineering, Electrical & Electronic
Osman Goni, Vladimir Okhmatovski
Summary: The study presents the exact solution of the surface-volume-surface electric field integral equation (SVS-EFIE) for the radiation problem near a dielectric sphere, demonstrating high accuracy in the case of electric dipole radiation. The solution confirms the rigorous nature of the equation and reveals the spectral properties of the MoM impedance matrix.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2021)
Article
Engineering, Electrical & Electronic
Carlos Perez-Arancibia, Catalin Turc, Luiz M. Faria, Constantine Sideris
Summary: This article introduces an extension of the planewave density interpolation method to the electric-field integral equation (EFIE) for scattering and radiation by perfect electric conducting objects. The technique simplifies calculations by regularizing kernel singularities and enables effective treatment of multiscale and complex structures.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2021)
Article
Engineering, Electrical & Electronic
Jinbo Liu, Jiming Song, Hui Zhang, Zengrui Li
Summary: This paper proposes a novel VSIE method for solving the current distribution on both sides of the open PEC surfaces for open perfect electric conductor (PEC)-dielectric objects. Both electric and magnetic field integral equations are established on both sides of the PEC surfaces, and basic functions are defined at the borders to consider current flowing over the edges. Compared to traditional VSIE, the proposed method has limited added CPU time due to the asynchronous solution processes of the surface current, with the memory usage being the same. Numerical results confirm the validity and efficiency of the proposed method.
IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS
(2022)
Article
Computer Science, Information Systems
Han Wang, Mingjie Pang, Hai Lin
Summary: The general matrix equation (GME) is proposed for electromagnetic scattering from arbitrary metal-dielectric composite objects, offering an enhanced solution for more complex structures. Accelerated solving policies based on coupling degree are introduced for GME to improve efficiency.
FRONTIERS OF INFORMATION TECHNOLOGY & ELECTRONIC ENGINEERING
(2022)
Article
Engineering, Electrical & Electronic
Benjamin G. Ward
Summary: This article introduces a new method for electromagnetic analysis of heterogeneous dielectric bodies with embedded PEC structures. The method provides more accurate results and high computational efficiency.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2021)
Article
Engineering, Electrical & Electronic
Ioannis P. Georgakis, Ilias I. Giannakopoulos, Mikhail S. Litsarev, Athanasios G. Polimeridis
Summary: A stable volume integral equation (VIE) solver based on polarization/magnetization currents is presented for accurate and efficient computation of electromagnetic scattering. The formulation is discretized using the Galerkin method with discontinuous piecewise linear basis functions on uniform voxelized grids, allowing for accelerated matrix-vector products in an iterative solver with the help of FFT.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2021)
Article
Engineering, Electrical & Electronic
Xiao-Wei Huang, Ming-Lin Yang, Xin-Qing Sheng
Summary: This article analyzes the mechanism of each term in the discontinuous Galerkin method and proposes a more flexible and memory-saving DG self-dual integral equation for solving electromagnetic scattering from large-scale objects with impedance boundary condition. The massively parallel strategy of the MLFMA is employed to further enhance its capability for electrically large problems, demonstrating the accuracy and efficiency of the proposed formulation for analyzing electromagnetic scattering problems.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2022)
Article
Engineering, Electrical & Electronic
Hanru Shao, Kunpeng Fu, Zhengxuan Fu, Xiaojie Ying, Jun Hu
Summary: In this paper, a fast model order reduction method is proposed to solve the electromagnetic scattering of large periodic arrays consisting of connected elements. By introducing equivalence surfaces and a new method based on grid, the evaluation challenge of traditional basis functions when the surfaces intersect with current-carrying conductors is effectively handled. Moreover, by constructing characteristic basis functions and applying multilevel fast multipole algorithm and sparse approximate inverse preconditioner, the solution process of large periodic arrays is accelerated.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2023)
Article
Mathematics, Applied
H. Sakly, G. Matoussi
Summary: We study the scattering of time-harmonic electromagnetic waves by inhomogeneous anisotropic media. By considering an orthotropic cylindrical obstacle and fields that do not vary along the axis of the cylinder, we can reduce the problem to a two-dimensional one. The problem can be equivalently written using two strongly singular volume integral equations (VIEs), one vector-valued and the other scalar-valued. The main goal of this study is to analyze the essential spectrum of the integral operators that describe these VIEs, given that the physical parameters are piecewise valued matrix functions with certain bounds on their eigenvalues. By considering Lipschitz interfaces, we show that the spectrum is contained within subsets that depend on the spectral properties of the scattering parameters. These results on the spectrum are then used to derive sufficient conditions for the uniqueness of solutions to the diffraction problem.
JOURNAL OF MATHEMATICAL ANALYSIS AND APPLICATIONS
(2024)
Article
Engineering, Electrical & Electronic
Vit Losenicky, Lukas Jelinek, Miloslav Capek, Mats Gustafsson
Summary: This article develops hybrid computational schemes that combine the advantages of the method of moments formulation of a field integral equation and T-matrix method. The performance of the method is tested on a spherical multilayer model of the human head, demonstrating its superiority compared to conventional approaches.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2022)
Article
Engineering, Electrical & Electronic
Victor F. Martin, Diego M. Solis, Marta G. Araujo, Luis Landesa, Fernando Obelleiro, Jose M. Taboada
Summary: An electric field integral equation (EFIE) discontinuous Galerkin (DG) formulation is proposed in this paper for the electromagnetic (EM) radiation analysis of realistic antennas. The formulation allows for separately building and meshing parts with different characteristics, which is useful for complex multiscale geometries and design optimization processes.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2023)
Article
Engineering, Electrical & Electronic
Beibei Kong, Pasi Yla-Oijala, Ari Sihvola
Summary: A surface integral equation (SIE) method has been developed for analyzing electromagnetic scattering by 3-D objects with soft-and-hard/DB (SHDB) boundary conditions. By expressing the SHDB boundary condition in vector form and combining it with tangential field integral equations, a more stable system is obtained for numerical simulations and comparisons. The proposed nonsquare integral equation solutions have been verified using physical optics approximations.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2021)
Article
Engineering, Electrical & Electronic
Mohammad Shafieipour, Moein Nazari, Farid P. Dawalibi, Simon Fortin, Akiyoshi Tatematsu, Jeewantha De Silva, Pablo Gomez
Summary: This paper presents a method that converts frequency domain solutions obtained from the method of moments (MoM) discretization of the electric field integral equation (EFIE) to time domain using the numerical Laplace transform (NLT). This method enables fast and accurate 3-D electromagnetic transient (EMT) analysis for a wide range of power system applications. Experimental measurements, finite-difference time domain method, and EMT-type software results confirm the validity of this method for handling power system transients in the range of microseconds down to nanoseconds.
IEEE TRANSACTIONS ON POWER DELIVERY
(2023)
Article
Engineering, Electrical & Electronic
Bo-Wen Xue, Rui Guo, Mao-Kun Li, Sheng Sun, Xiao-Min Pan
Summary: DL-equipped iterators are developed to accelerate the iterative solution of electromagnetic scattering problems. DL blocks consisting of U-nets are employed to replace the nonlinear process of traditional iterators. The proposed complex-valued batch normalization in the U-net improves the computational time and accuracy of the DL-equipped iterators by properly handling phase information.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2023)
Article
Physics, Applied
Ying Pan, Rasmus E. Christiansen, Jerome Michon, Juejun Hu, Steven G. Johnson
Summary: Surface-enhanced Raman spectroscopy (SERS) is a powerful sensing method with the potential to detect single molecules, and topology optimization (TopOpt) can be used to design SERS substrates adhering to realistic fabrication constraints. By relaxing the fabrication minimum-feature-size constraint, TopOpt can be used to design SERS substrates with orders of magnitude larger enhancement factors. The results validate topology optimization as an effective method for engineering optimized SERS nanostructures adhering to fabrication limitations.
APPLIED PHYSICS LETTERS
(2021)
Article
Optics
Alec M. Hammond, Ardavan Oskooi, Steven G. Johnson, Stephen E. Ralph
Summary: This study presents a unified density-based topology optimization framework for optimizing integrated photonic designs for manufacturing constraints such as minimum area, minimum enclosed area, linewidth, linespacing, and curvature. Differentiable morphological transforms are utilized to create devices that are robust to etching issues and meet manufacturing constraints.
Article
Physics, Applied
Fan Wang, Steven G. Johnson, Henry O. Everitt
Summary: The performance of powerful tunable narrow-band continuous-wave terahertz radiation lasers heavily relies on molecular collision physics, pump saturation, and laser cavity design. An optimized laser cavity can produce tens of milliwatts of power tunable over frequencies above 1 THz when pumped by a multiwatt QCL.
PHYSICAL REVIEW APPLIED
(2021)
Article
Optics
Alec M. Hammond, Ardavan Oskooi, Mo Chen, Zin Lin, Steven G. Johnson, Stephen E. Ralph
Summary: We present a photonics topology optimization (TO) package that can address a wide range of practical photonics design problems. The package incorporates robustness and manufacturing constraints and can scale to large devices and massive parallelism. It employs a hybrid algorithm that solves multiple frequency-domain TO problems using a mature time-domain (FDTD) package and is enhanced by new filter-design sources and material-interpolation methods.
Article
Optics
Zin Lin, Raphael Pestourie, Charles Roques-Carmes, Zhaoyi Li, Federico Capasso, Marin Soljacic, Steven G. Johnson
Summary: We introduce end-to-end inverse design for multi-channel imaging, which involves optimizing a nanophotonic frontend and an image-processing backend to extract depth, spectral, and polarization channels from a single monochrome image. We demonstrate that subwavelength-scale metasurface designs can easily distinguish similar wavelength and polarization inputs, unlike diffractive optics. Our proposed technique combines a single-layer metasurface frontend with an efficient Tikhonov reconstruction backend, requiring only a grayscale sensor. Through spontaneous demultiplexing, our method achieves multi-channel imaging by separating different channels into distinct spatial domains on the sensor. We present large-area metasurface designs for multi-spectral imaging, depth-spectral imaging, and all-in-one spectro-polarimetric-depth imaging, demonstrating robust reconstruction performance.
Article
Physics, Applied
Mohammed Benzaouia, John D. Joannopoulos, Steven G. Johnson, Aristeidis Karalis
Summary: This study presents general analytical criteria for designing standard filters and demonstrates the method of designing filter devices through specific unitary coupling ratios. By solving a nonlinear optimization problem, filter design can be achieved, with a focus on elliptic filters for optimal performance.
PHYSICAL REVIEW APPLIED
(2022)
Article
Optics
Wenjie Yao, Francesc Verdugo, Henry O. Everit, Rasmus E. Christiansen, Steven G. Johnson
Summary: We propose a general framework for inverse design of nanopatterned surfaces that maximize surface-enhanced Raman spectra from randomly distributed molecules. Our optimized structures outperform coating with optimized spheres or bowtie structures by about 4 and 20 times, respectively, when considering nonlinear damage effects.
Article
Computer Science, Interdisciplinary Applications
Giuseppe Romano, Steven G. Johnson
Summary: In this study, a methodology for density-based topology optimization of non-Fourier thermal transport in nanostructures is introduced. It utilizes adjoint-based sensitivity analysis of the phonon Boltzmann transport equation (BTE) and a novel material interpolation technique called the transmission interpolation model (TIM). The approach is able to handle the interplay between real- and momentum-resolved material properties by parameterizing the material density with an interfacial transmission coefficient. This methodology allows for the systematic optimization of materials for heat management and conversion, as well as the design of devices where diffusive transport is not valid.
STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION
(2022)
Article
Nanoscience & Nanotechnology
Pengning Chao, Rodrick Kuate Defo, Sean Molesky, Alejandro Rodriguez
Summary: The local density of states (LDOS) plays a crucial role in photonics engineering. We propose a framework for evaluating upper bounds on LDOS in structured media, which can handle arbitrary bandwidths and considers wave scattering effects. We derive an analytical expression for the maximum LDOS and discover scaling laws for maximum LDOS enhancement, with implications on material selection and design applications.
Article
Optics
Mohammed Benzaouia, A. D. Stone, Steven G. Johnson
Summary: In this study, a general analysis is presented for finding and characterizing nonlinear exceptional point (EP) lasers above threshold. The stability of the EP laser is confirmed through numerical analysis, and a new method for characterizing the EP laser is proposed.
Article
Optics
Sophie Fisher, Raphael Pestourie, Steven G. Johnson
Summary: This study presents a semianalytical framework for computing the coupling of radiative and guided waves in slowly varying surfaces. It fills the gap in current approximate methods by allowing the modeling of their coupling using a combination of two methods.
Article
Physics, Multidisciplinary
Lu Lu, Raphael Pestourie, Steven G. Johnson, Giuseppe Romano
Summary: This paper proposes a multifidelity neural operator based on deep neural networks, which can reduce the demand for high-fidelity data and achieve smaller errors in solving heat transport problems. By combining with genetic algorithms and topology optimization, it enables fast solvers and inverse design for the phonon Boltzmann transport equation (BTE).
PHYSICAL REVIEW RESEARCH
(2022)
Article
Materials Science, Multidisciplinary
Chinmay Khandekar, Siddharth Buddhiraju, Paul R. Wilkinson, James K. Gimzewski, Alejandro W. Rodriguez, Charles Chase, Shanhui Fan
Summary: This study demonstrates that an isotropic dipolar particle near an asymmetric medium surface may experience lateral force and torque when the particle's temperature differs from the surrounding environment. The presence of the lateral force is associated with the asymmetric dispersion of nonreciprocal surface polaritons, while the presence of lateral torque is linked to the spin-momentum locking of surface waves. Additionally, it is found that the directions of the lateral force and torque are dependent on the constituent materials of the particles.
Article
Materials Science, Multidisciplinary
Yi-Xin Sha, Bo-Yuan Liu, Hao-Zhe Gao, Heng-Bin Cheng, Hai-Li Zhang, Ming-Yao Xia, Steven G. Johnson, Ling Lu
Summary: The iterative Green's function based on cyclic reduction of block-tridiagonal matrices is an ideal algorithm to compute the surface density of states of semi-infinite topological electronic materials. This method is applied to photonic and acoustic crystals using finite-element discretization and a generalized eigenvalue formulation to calculate the local density of states on a single surface of semi-infinite lattices. Three-dimensional examples of gapless helicoidal surface states in Weyl and Dirac crystals are shown, and the computational cost, convergence, and accuracy are analyzed.
Article
Physics, Multidisciplinary
Mohammed Benzaouia, John D. Joannopoulos, Steven G. Johnson, Aristeidis Karalis
Summary: Researchers have developed a quasi-normal mode theory for calculating a system's scattering S matrix, which simultaneously satisfies energy conservation and reciprocity. This practical reduced-order model is based on resonant frequencies and constant mode-to-port coupling coefficients, and can easily compute and describe various electromagnetic metasurfaces' Fano resonant phenomena.
PHYSICAL REVIEW RESEARCH
(2021)