Beibei Kong - Academia.edu (original) (raw)

Papers by Beibei Kong

Research paper thumbnail of Electromagnetic Scattering Analysis of SHDB Objects Using Surface Integral Equation Method

Photonics, 2020

A surface integral equation (SIE) method is applied in order to analyze electromagnetic scatterin... more A surface integral equation (SIE) method is applied in order to analyze electromagnetic scattering by bounded arbitrarily shaped three-dimensional objects with the SHDB boundary condition. SHDB is a generalization of SH (Soft-and-Hard) and DB boundary conditions (at the DB boundary, the normal components of the D and B flux densities vanish). The SHDB boundary condition is a general linear boundary condition that contains two scalar equations that involve both the tangential and normal components of the electromagnetic fields. The multiplication of these scalar equations with two orthogonal vectors transforms them into a vector form that can be combined with the tangential field integral equations. The resulting equations are discretized and converted to a matrix equation with standard method of moments (MoM). As an example of use of the method, we investigate scattering by an SHDB circular disk and demonstrate that the SHDB boundary allows for an efficient way to control the polari...

Research paper thumbnail of Surface Integral Equation Method for Generalized Soft-and-Hard Boundary Condition

IEEE Transactions on Antennas and Propagation, 2020

A surface integral equation (SIE) method is developed for analyzing electromagnetic scattering by... more A surface integral equation (SIE) method is developed for analyzing electromagnetic scattering by objects with generalized soft-and-hard (GSH) boundary conditions. GSH boundary condition is an anisotropic impedance boundary condition, which limits the tangential electric and magnetic fields in specified directions. In the developed SIE formulation, the GSH boundary condition is expressed in a vector form with two sets of orthogonal vectors, which can be combined with the field integral equations. The resulting equation can be discretized with the standard method of moments (MoM) using triangular elements and the Rao-Wilton-Glisson (RWG) functions. By varying the GSH condition the direction of the tangential electric and magnetic fields on the surface can be flexibly changed.

Research paper thumbnail of A Discontinuous Galerkin Surface Integral Solution for Scattering From Homogeneous Objects With High Dielectric Constant

IEEE Transactions on Antennas and Propagation, 2019

Research paper thumbnail of Modeling of Resonating Closed Impedance Bodies With Surface Integral Equation Methods

IEEE Transactions on Antennas and Propagation, 2018

Numerical solutions of various surface integral equation formulations in modeling resonating (los... more Numerical solutions of various surface integral equation formulations in modeling resonating (lossless) closed impedance bodies are investigated. It is demonstrated that for certain values of purely imaginary surface impedances very strongly resonating field solutions can appear. Some of the considered formulations that are known to work well outside these resonances, e.g., for lossy surfaces, can lead to very poor accuracy or even diverging solutions at these resonances. Among the considered formulations only the combined source integral equations, discretized with a mixed scheme, both avoid the nonphysical spurious internal resonances and work reasonably well at the physical (impedance) resonances.

Research paper thumbnail of Simple and Efficient Preconditioner for Surface Integral Solution of Scattering from Multilayer Dielectric Bodies

International Journal of Antennas and Propagation, 2016

The computation of scattering from multilayer dielectric bodies is studied by using the combined ... more The computation of scattering from multilayer dielectric bodies is studied by using the combined tangential formulation (CTF) of surface integral solution. A simple and efficient preconditioner is designed for the surface integral solution of multilayer dielectric bodies and validated by numerical experiments. Compared with the traditional near field preconditioner, the proposed preconditioner significantly reduce CPU time and memory requirement. Furthermore, the multilevel fast multipole algorithm (MLFMA) is employed to improve the capability of the solutions. The trick of efficiently implementing MLFMA is presented for multilayer dielectric bodies. Numerical examples are presented to verify the accuracy and efficiency of the approach for computing scattering from multilayer dielectric problems.

Research paper thumbnail of Effects of the coupling of dielectric spherical particles on signatures in infrared microspectroscopy

Infrared microspectroscopy is a powerful tool in the analysis of biological samples. However, str... more Infrared microspectroscopy is a powerful tool in the analysis of biological samples. However, strong electromagnetic scattering may occur since the wavelength of the incident radiation and the samples may be of comparable size. Based on the Mie theory of single spheres, correction algorithms have been developed to retrieve pure absorbance spectra. Studies of the scattering characteristics of samples of different types, obtained by microspectroscopy, have been performed. However, the detailed,microscopic effects of the coupling of the samples on signatures in spectra, obtained by infrared microspectroscopy, are still notclear. The aim of this paper is to investigate how the coupling of spherical samples influences the spectra. Applying the surfaceintegral equation (SIE) method, we simulate small dielectric spheres, arranged as double-spheres or small arrays of spheres.We find that the coupling of the spheres hardly influences the broad oscillations observed in infrared spectra (the M...

Research paper thumbnail of Scattering, extinction and albedo of impedance-boundary objects

URSI Radio Science Letters, 1999

This article presents results on the scattering and absorption behavior of lossy impedanceboundar... more This article presents results on the scattering and absorption behavior of lossy impedanceboundary spheres and cubes. The albedo (the ratio between the scattering and extinction cross sections) of these scatterers turns out to be a very insightful quantity in this respect. The strongly nonlinear dependence of albedo on the size of the objects is illustrated and compared with the albedo of dissipative penetrable spheres. The shape of the object seems to have surprisingly little effect on the albedo. Furthermore, the effect of losses on the resonance behavior of small impedance-boundary spheres is analyzed, leading to the observation that the dipolar mode vanishes from the albedo spectrum, while higher order multipoles remain visible. This resembles a similar phenomenon earlier shown to appear in connection with small plasmonic scatterers.

Research paper thumbnail of Surface Integral Equation Method for Soft-and-Hard/DB Boundary Condition

IEEE Transactions on Antennas and Propagation, 2021

A surface integral equation (SIE) method is developed to analyze electromagnetic scattering by 3-... more A surface integral equation (SIE) method is developed to analyze electromagnetic scattering by 3-D objects with soft-and-hard/DB (SHDB) boundary conditions. The SHDB boundary condition is a generalization of the soft-and-hard (SH) and DB boundary conditions that associate the normal and tangential field components on the boundary. In the developed method, the SHDB boundary condition is expressed in vector form that allows combining it with the tangential field integral equations. The obtained equations can be discretized with the standard method of moments (MoM) using the Rao–Wilton–Glisson (RWG) functions. Different combinations of the integral equations and boundary conditions are derived, and their numerical performance is studied and compared. It is demonstrated with numerical experiments that a much more stable system is obtained by considering the boundary conditions as extra equations, rather than integrating them into the SIEs. The solutions of the proposed nonsquare integral equation are verified with the physical optics approximations.

Research paper thumbnail of Electromagnetic Scattering Analysis of SHDB Objects Using Surface Integral Equation Method

Photonics, 2020

A surface integral equation (SIE) method is applied in order to analyze electromagnetic scatterin... more A surface integral equation (SIE) method is applied in order to analyze electromagnetic scattering by bounded arbitrarily shaped three-dimensional objects with the SHDB boundary condition. SHDB is a generalization of SH (Soft-and-Hard) and DB boundary conditions (at the DB boundary, the normal components of the D and B flux densities vanish). The SHDB boundary condition is a general linear boundary condition that contains two scalar equations that involve both the tangential and normal components of the electromagnetic fields. The multiplication of these scalar equations with two orthogonal vectors transforms them into a vector form that can be combined with the tangential field integral equations. The resulting equations are discretized and converted to a matrix equation with standard method of moments (MoM). As an example of use of the method, we investigate scattering by an SHDB circular disk and demonstrate that the SHDB boundary allows for an efficient way to control the polari...

Research paper thumbnail of Surface Integral Equation Method for Generalized Soft-and-Hard Boundary Condition

IEEE Transactions on Antennas and Propagation, 2020

A surface integral equation (SIE) method is developed for analyzing electromagnetic scattering by... more A surface integral equation (SIE) method is developed for analyzing electromagnetic scattering by objects with generalized soft-and-hard (GSH) boundary conditions. GSH boundary condition is an anisotropic impedance boundary condition, which limits the tangential electric and magnetic fields in specified directions. In the developed SIE formulation, the GSH boundary condition is expressed in a vector form with two sets of orthogonal vectors, which can be combined with the field integral equations. The resulting equation can be discretized with the standard method of moments (MoM) using triangular elements and the Rao-Wilton-Glisson (RWG) functions. By varying the GSH condition the direction of the tangential electric and magnetic fields on the surface can be flexibly changed.

Research paper thumbnail of A Discontinuous Galerkin Surface Integral Solution for Scattering From Homogeneous Objects With High Dielectric Constant

IEEE Transactions on Antennas and Propagation, 2019

Research paper thumbnail of Modeling of Resonating Closed Impedance Bodies With Surface Integral Equation Methods

IEEE Transactions on Antennas and Propagation, 2018

Numerical solutions of various surface integral equation formulations in modeling resonating (los... more Numerical solutions of various surface integral equation formulations in modeling resonating (lossless) closed impedance bodies are investigated. It is demonstrated that for certain values of purely imaginary surface impedances very strongly resonating field solutions can appear. Some of the considered formulations that are known to work well outside these resonances, e.g., for lossy surfaces, can lead to very poor accuracy or even diverging solutions at these resonances. Among the considered formulations only the combined source integral equations, discretized with a mixed scheme, both avoid the nonphysical spurious internal resonances and work reasonably well at the physical (impedance) resonances.

Research paper thumbnail of Simple and Efficient Preconditioner for Surface Integral Solution of Scattering from Multilayer Dielectric Bodies

International Journal of Antennas and Propagation, 2016

The computation of scattering from multilayer dielectric bodies is studied by using the combined ... more The computation of scattering from multilayer dielectric bodies is studied by using the combined tangential formulation (CTF) of surface integral solution. A simple and efficient preconditioner is designed for the surface integral solution of multilayer dielectric bodies and validated by numerical experiments. Compared with the traditional near field preconditioner, the proposed preconditioner significantly reduce CPU time and memory requirement. Furthermore, the multilevel fast multipole algorithm (MLFMA) is employed to improve the capability of the solutions. The trick of efficiently implementing MLFMA is presented for multilayer dielectric bodies. Numerical examples are presented to verify the accuracy and efficiency of the approach for computing scattering from multilayer dielectric problems.

Research paper thumbnail of Effects of the coupling of dielectric spherical particles on signatures in infrared microspectroscopy

Infrared microspectroscopy is a powerful tool in the analysis of biological samples. However, str... more Infrared microspectroscopy is a powerful tool in the analysis of biological samples. However, strong electromagnetic scattering may occur since the wavelength of the incident radiation and the samples may be of comparable size. Based on the Mie theory of single spheres, correction algorithms have been developed to retrieve pure absorbance spectra. Studies of the scattering characteristics of samples of different types, obtained by microspectroscopy, have been performed. However, the detailed,microscopic effects of the coupling of the samples on signatures in spectra, obtained by infrared microspectroscopy, are still notclear. The aim of this paper is to investigate how the coupling of spherical samples influences the spectra. Applying the surfaceintegral equation (SIE) method, we simulate small dielectric spheres, arranged as double-spheres or small arrays of spheres.We find that the coupling of the spheres hardly influences the broad oscillations observed in infrared spectra (the M...

Research paper thumbnail of Scattering, extinction and albedo of impedance-boundary objects

URSI Radio Science Letters, 1999

This article presents results on the scattering and absorption behavior of lossy impedanceboundar... more This article presents results on the scattering and absorption behavior of lossy impedanceboundary spheres and cubes. The albedo (the ratio between the scattering and extinction cross sections) of these scatterers turns out to be a very insightful quantity in this respect. The strongly nonlinear dependence of albedo on the size of the objects is illustrated and compared with the albedo of dissipative penetrable spheres. The shape of the object seems to have surprisingly little effect on the albedo. Furthermore, the effect of losses on the resonance behavior of small impedance-boundary spheres is analyzed, leading to the observation that the dipolar mode vanishes from the albedo spectrum, while higher order multipoles remain visible. This resembles a similar phenomenon earlier shown to appear in connection with small plasmonic scatterers.

Research paper thumbnail of Surface Integral Equation Method for Soft-and-Hard/DB Boundary Condition

IEEE Transactions on Antennas and Propagation, 2021

A surface integral equation (SIE) method is developed to analyze electromagnetic scattering by 3-... more A surface integral equation (SIE) method is developed to analyze electromagnetic scattering by 3-D objects with soft-and-hard/DB (SHDB) boundary conditions. The SHDB boundary condition is a generalization of the soft-and-hard (SH) and DB boundary conditions that associate the normal and tangential field components on the boundary. In the developed method, the SHDB boundary condition is expressed in vector form that allows combining it with the tangential field integral equations. The obtained equations can be discretized with the standard method of moments (MoM) using the Rao–Wilton–Glisson (RWG) functions. Different combinations of the integral equations and boundary conditions are derived, and their numerical performance is studied and compared. It is demonstrated with numerical experiments that a much more stable system is obtained by considering the boundary conditions as extra equations, rather than integrating them into the SIEs. The solutions of the proposed nonsquare integral equation are verified with the physical optics approximations.