scholarly journals Analysis of electromagnetic scattering from plasmonic inclusions beyond the quasi-static approximation and applications

2019 ◽  
Vol 53 (4) ◽  
pp. 1351-1371 ◽  
Author(s):  
Hongjie Li ◽  
Shanqiang Li ◽  
Hongyu Liu ◽  
Xianchao Wang
Keyword(s):  
Surface Plasmon ◽  
Electromagnetic Scattering ◽  
Scattering Problem ◽  
Spherical Geometry ◽  
Layer Potential ◽  
Static Approximation ◽  
Quasi Static Approximation ◽  
Plasmonic Structures ◽  
Time Harmonic ◽  
Frequency Regime

This paper is concerned with the analysis of time-harmonic electromagnetic scattering from plasmonic inclusions in the finite frequency regime beyond the quasi-static approximation. The electric permittivity and magnetic permeability in the inclusions are allowed to be negative-valued. Using layer potential techniques for the full Maxwell system, the scattering problem is reformulated into a system of integral equations. We derive the complete eigensystem of the involved matrix-valued integral operator within spherical geometry. As applications, we construct two types of plasmonic structures such that one can induce surface plasmon resonances within finite frequencies and the other one can produce invisibility cloaking. It is particularly noted that the cloaking effect is a newly found phenomenon and is of different nature from those existing ones for plasmonic structures in the literature. The surface plasmon resonance result may find applications in electromagnetic imaging.

scholarly journals Dipolar Excitation of a Perfectly Electrically Conducting Spheroid in a Lossless Medium at the Low-Frequency Regime

2018 ◽  
Vol 2018 ◽  
pp. 1-20 ◽  
Author(s):  
Panayiotis Vafeas
Keyword(s):  
Electric Fields ◽  
Vector Fields ◽  
Dimensional Space ◽  
Scattering Problem ◽  
Low Frequency ◽  
Main Idea ◽  
Wave Number ◽  
Low Frequencies ◽  
Static Approximation ◽  
Frequency Regime

The electromagnetic vector fields, which are scattered off a highly conductive spheroid that is embedded within an otherwise lossless medium, are investigated in this contribution. A time-harmonic magnetic dipolar source, located nearby and operating at low frequencies, serves as the excitation primary field, being arbitrarily orientated in the three-dimensional space. The main idea is to obtain an analytical solution of this scattering problem, using the appropriate system of spheroidal coordinates, such that a possibly fast numerical estimation of the scattered fields could be useful for real data inversion. To this end, incident and scattered as well as total fields are written in a rigorous low-frequency manner in terms of positive integral powers of the real-valued wave number of the exterior environment. Then, the Maxwell-type problem is converted to interconnected Laplace’s or Poisson’s equations, complemented by the perfectly conducting boundary conditions on the spheroidal object and the necessary radiation behavior at infinity. The static approximation and the three first dynamic contributors are sufficient for the present study, while terms of higher orders are neglected at the low-frequency regime. Henceforth, the 3D scattering boundary value problems are solved incrementally, whereas the determination of the unknown constant coefficients leads either to concrete expressions or to infinite linear algebraic systems, which can be readily solved by implementing standard cut-off techniques. The nonaxisymmetric scattered magnetic and electric fields follow and they are obtained in an analytical compact fashion via infinite series expansions in spheroidal eigenfunctions. In order to demonstrate the efficiency of our analytical approach, the results are degenerated so as to recover the spherical case, which validates this approach.

scholarly journals Analysis Method for the Heating of the Human Eye Exposed to High Frequency Electromagnetic Fields

2007 ◽  
Vol 3 (1) ◽  
pp. 3 ◽  
Author(s):  
Andrés Peratta ◽  
Dragan Poljak
Keyword(s):  
Electromagnetic Scattering ◽  
High Frequency ◽  
Electromagnetic Waves ◽  
Specific Absorption Rate ◽  
Scattering Problem ◽  
Analysis Method ◽  
Human Eye ◽  
Time Harmonic ◽  
Standard Finite Element Method ◽  
Frequency Radiation

The paper studies the thermal rise in the human eye caused by time harmonic electromagnetic waves. An eye has been illuminated by a high frequency plane wave with powerdensity 5.0 mW/cm2. Such a problem has been considered as an electromagnetic scattering problem since part of EM energy is transmitted to the eye and part of it is reflected. The total electric field inside an eye and related Specific Absorption Rate (SAR) has been calculated in a frequency range from 0.7 to 4.4 GHz via a hybrid BEM/FEM approach. Knowing the SAR distribution inside the eye provides the calculation of related temperature rise in the human eye due to high frequency radiation by solving Bio-Heat Transfer Equation via standard finite element method.

scholarly journals A UNIQUENESS THEOREM FOR AN INVERSE ELECTROMAGNETIC SCATTERING PROBLEM IN INHOMOGENEOUS ANISOTROPIC MEDIA

2003 ◽  
Vol 46 (2) ◽  
pp. 293-314 ◽  
Author(s):  
Fioralba Cakoni ◽  
David Colton
Keyword(s):  
Anisotropic Medium ◽  
Electromagnetic Scattering ◽  
Maxwell’S Equations ◽  
Maxwell's Equations ◽  
Scattering Problem ◽  
Plane Waves ◽  
Field Patterns ◽  
Regularity Properties ◽  
Time Harmonic ◽  
Secondary 35P25

AbstractWe show that the support of a (possibly) coated anisotropic medium is uniquely determined by the electric far-field patterns corresponding to incident time-harmonic electromagnetic plane waves with arbitrary polarization and direction. Our proof avoids the use of a fundamental solution to Maxwell’s equations in an anisotropic medium and instead relies on the well-posedness and regularity properties of solutions to an interior transmission problem for Maxwell’s equations.AMS 2000 Mathematics subject classification: Primary 35R30; 35Q60. Secondary 35P25; 78A45

The inverse elastic scattering by an impenetrable obstacle and a crack

2020 ◽  
Author(s):  
Jianli Xiang ◽  
Guozheng Yan
Keyword(s):  
Mixed Type ◽  
Scattering Problem ◽  
Inverse Scattering Problem ◽  
Field Operator ◽  
Integral Equation Method ◽  
Factorization Method ◽  
Boundary Integral ◽  
Far Field ◽  
Direct Scattering ◽  
Time Harmonic

Abstract This paper is concerned with the inverse scattering problem of time-harmonic elastic waves by a mixed-type scatterer, which is given as the union of an impenetrable obstacle and a crack. We develop the modified factorization method to determine the shape of the mixed-type scatterer from the far field data. However, the factorization of the far field operator $F$ is related to the boundary integral matrix operator $A$, which is obtained in the study of the direct scattering problem. So, in the first part, we show the well posedness of the direct scattering problem by the boundary integral equation method. Some numerical examples are presented at the end of the paper to demonstrate the feasibility and effectiveness of the inverse algorithm.

scholarly journals A study of coupling interactions in finite arbitrarily-shaped grooves in electromagnetic scattering problem

2010 ◽  
Vol 18 (3) ◽  
pp. 2743 ◽  
Author(s):  
M. A. Basha ◽  
S. Chaudhuri ◽  
S. Safavi-Naeini
Keyword(s):  
Electromagnetic Scattering ◽  
Scattering Problem

STRONG AND WEAK FORMS OF THE METHOD OF MOMENTS AND THE COUPLED DIPOLE METHOD FOR SCATTERING OF TIME-HARMONIC ELECTROMAGNETIC FIELDS

1992 ◽  
Vol 03 (03) ◽  
pp. 583-603 ◽  
Author(s):  
AKHLESH LAKHTAKIA
Keyword(s):  
Electromagnetic Fields ◽  
Method Of Moments ◽  
Electromagnetic Scattering ◽  
Final Section ◽  
The Other ◽  
Numerical Techniques ◽  
Scattering Problems ◽  
Time Harmonic

Algorithms based on the method of moments (MOM) and the coupled dipole method (CDM) are commonly used to solve electromagnetic scattering problems. In this paper, the strong and the weak forms of both numerical techniques are derived for bianisotropic scatterers. The two techniques are shown to be fully equivalent to each other, thereby defusing claims of superiority often made for the charms of one technique over the other. In the final section, reductions of the algorithms for isotropic dielectric scatterers are explicitly given.

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