Modified Spherical Wave Functions With Anisotropy Ratio: Application to the Analysis of Scattering by Multilayered Anisotropic Shells

Abstract

Abstract-We describe a novel and rigorous vector eigenfunction expansion of electric-type Green's dyadics for radially multilayered uniaxial anisotropic media in terms of the modified spherical vector wave functions, which can take into account the effects of anisotropy ratio systematically. In each layer, the material constitutions and are tensors and distribution of sources is arbitrary. Both the unbounded and scattering dyadic Green's functions (DGFs) for rotationally uniaxial anisotropic media are derived in spherical coordinates ( ). The coefficients of scattering DGFs, based on the coupling recursive algorithm satisfied by the coefficient matrix, are derived and expressed in a compact form. With these DGFs obtained, the electromagnetic fields in each layer are straightforward once the current source is known. A specific model is proposed for the scattering and absorption characteristics of multilayered uniaxial anisotropic spheres, and some novel performance regarding anisotropy effects is revealed.Index Terms-Anisotropic ratio, dyadic Green's functions (DGFs), modified spherical wave functions, radially multilayered structures, recurrence matrix, scattering and absorption, vector eigenfunction expansion.

Anisotropic Scattering Characteristics of a Radially Multilayered Gyrotropic Sphere

“…International Journal of Antennas and Propagation 3 (E inc , H inc ) are the scattered and incident fields expanded by VSWFs (see (26) and (28) in [23] for details). Based on the boundary conditions, we can obtain the following recurrent formulation:…”

“…In the last several decades, a few analytical approaches have been developed based on the Cartesian coordinate expression of permittivity and permeability tensors, such as the perturbation expansion method [10,11], the method of expanding EM fields in gyrotropic media using a complete set of VSWFs [12], the method of adopting VSWFs combined with Fourier transform [13][14][15], dyadic Green's functions method [16][17][18], and the -matrix method [19][20][21][22][23]. To study the spherical anisotropy, Qiu et al have investigated the characteristics of radial anisotropic uniaxial and gyrotropic sphere, where the permittivity and permeability tensors are expressed in spherical coordinate [24][25][26][27][28][29][30]. Due to the completeness and noncoplanar properties of VSWFs, any three-dimensional vector function satisfying the vector Helmholtz equation can be expanded as a linear combinations of VSWFs [31].…”

Analysis of Scattering by Large Inhomogeneous Bi-Anisotropic Objects Using Aim

“…Bianisotropic media incorporates large variety of media, such as chiral or bi-isotropic media, gyrotropic chiral media, Faraday chiral media, anisotropic media, and gyrotropic media. Various applications utilizing bi-anisotropic media have been proposed such as angle-sensitive beam-shaping cover for antennas [2], negative refractive index [3][4][5], giant negative Goos-Hänchen shifter [6], polarization transformer [7], electromagnetic transparent coatings and shielding [8,9], scattering enhancement by radial anisotropy [10,11], and RF circuits [12].…”

Influence of spherical anisotropy on the optical properties of plasmon resonant metallic nanoparticles

“…On the other hand, the study of electromagnetic interaction with anisotropic core-shell particles has attracted much attention owing to its promising applications in scattering enhancement or suppression, various nano-antennas and novel optical devices [12][13][14][15][16][17]. In general, two types of anisotropies exist in natural and artificially engineered materials: Cartesian anisotropy and spherical anisotropy [18].…”

“…Based on modified Mie scattering theory for the structure with spherical anisotropy [1,15], we investigate the extinction properties of core-shell nanospheres with spherical anisotropy based on full-wave electromagnetic theory instead of a quasistatic approximation as in [2]. We reveal the dependence of the optical properties of dipole and quadrupole plasmon resonant modes and field localization upon the degree of spherical anisotropy as well as the size of the nanoparticles.…”