Inhomogeneous Body Of Revolution Research Articles

The FIT-MoM Method for Analysis of Electromagnetic Scattering by Bodies-of-Revolution Embedded in Multilayered Media

In this article, the previously introduced finite-integration technique/method-of-moments (FIT-MoM) hybrid method, which is suited for the analysis of electromagnetic scattering by inhomogeneous bodies of revolution (BoRs), is generalized to problems involving multilayered environment. Due to the fact that BoR-typical azimuthal mode decomposition is used, appropriate modal Green's functions for multilayered media are given. They are responsible for source-field interactions within the region that is external with regard to the FIT part. Formulas for modal decomposition of incident plane wave fields as well as the approximation enabling computing fields produced by sources associated with individual modes in the far-zone are also provided.

Анализ фокусировки волн в усеченной линзе Гутмана

The problem of scattering of a plane electromagnetic wave by a truncated axisymmetric Gutman lens including calculation of the field inside the lens is considered. The problem is solved numerically using the hybrid projection method developed earlier for the general case of wave scattering by inhomogeneous bodies of revolution. New results are presented that demonstrate the accuracy of the method, as well as the field distribution in the Gutman lens, which characterize the features of wave focusing depending on the lens size, focal length, and position of the truncation plane.

Modification of a Projection Method for Analysis of Radiation of a Radial Dipole in the Presence of an Inhomogeneous Body of Revolution

The problem of radiation of a radial electric dipole located on the axis of rotation of an axisymmetric body consisting of a homogeneous dielectric sphere and an external inhomogeneous dielectric layer is considered. The new numerical algorithm developed to solve the problem is based on a projection method that includes the projection of fields to transverse spherical harmonics in combination with a one-dimensional finite element method in a projection form along the radial coordinate. The algorithm is also generalized to the case in which the inner sphere is perfectly conducting. Numerical results, which characterize both the efficiency of the method and the effect of various parameters of the body on the directional pattern of the dipole, are presented.

Modifications of the hybrid projection method for analysis of electromagnetic scattering by inhomogeneous bodies of revolution.

A numerical analysis of wave scattering by a body of revolution composed of a homogeneous dielectric sphere and an external inhomogeneous dielectric layer with arbitrary generatrix is carried out. A modification of the hybrid projection method developed in the paper includes expansion of the fields in terms of transverse vector spherical functions, projection of the Maxwell's equations in the inhomogeneous region on the indicated functions, and use of the one-dimensional method of finite elements in projection form over the radial coordinate. Two more modifications correspond to the case of a perfectly conducting internal sphere and for the case of the absence of the internal sphere. The indicated modifications are realized in MATLAB codes for the case of excitation of the body by a circularly polarized plane wave propagating along the axis of revolution. Numerical results presented and discussed in the paper include the cases of wave scattering by a homogeneous sphere displaced from the origin of coordinates, a perfectly conducting sphere placed inside an inhomogeneous spheroidal layer, and a half-spherical Maxwell's fish-eye lens.

A Body-of-Revolution Implementation of the Parabolic Wave Equation With Application to Rocket Plume Attenuation Modeling

The parabolic wave equation has been used extensively to model long-range paraxial wave propagation due to its high computational efficiency. Typical radar, sonar, and communication geometries are most naturally treated using cylindrical coordinates with the radial direction chosen as the paraxial direction. Here, a method is described for modeling waves with 3-D variation propagating through an inhomogeneous body of revolution with the paraxial direction chosen to be the axis of symmetry. The technique decomposes the initial field into independent modes that are propagated in parallel using 2-D solvers. The method is benchmarked by comparison to finite-element calculations. An example application—modeling the interaction of a radio communications system with a rocket exhaust plume—is then considered.

A Method of Moments for Analysis of Electromagnetic Scattering From Inhomogeneous Anisotropic Bodies of Revolution

This paper proposes an efficient method to analyze scattering from an inhomogeneous body of revolution (BOR) with anisotropic electromagnetic properties. Both the permittivity and the permeability are assumed to be generalized tensors while there are no restrictions on the geometry of the BOR. The proposed method involves three stages. First, the volume equivalence principle is used to replace the BOR with volume electric and magnetic current densities. Requisite volume integral equations (VIEs) are, then, derived with the electric and magnetic flux densities inside the BOR being the unknown quantities. Finally, the VIEs are solved by Galerkin’s method of moments. This is done by expanding the unknown flux densities in terms of appropriate basis functions compatible with the problem symmetry, and hence, reducing the integral equations to a matrix equation. The formation of the resultant matrix equation is elucidated in detail, whereby it is shown that the computation burden is remarkably reduced as no double volumetric-type integrals are to be computed. The efficiency of the proposed method is demonstrated by comparing the simulation results of several case studies with those available in the literature, or computed by commercial numerical codes.

Electromagnetic computational method for the scattering of an axisymmetric laser beam by an inhomogeneous body of revolution

An original computational method for solving the two-dimensional problem of the scattering of an axisymmetric laser beam by an arbitrary-shaped inhomogeneous body of revolution is presented. This method relies on a domain decomposition of the scattering zone into concentric spherical radially homogeneous subdomains and on an expansion of the angular dependence of the fields on the Legendre functions. Numerical results for the fields obtained for various scatterer geometries are presented and analyzed.

Resonances in partially inhomogeneous bodies of revolution: VIE/SIE analysis

A method of moments (MoM) solution to analyze resonant frequencies and associated quality factors of partially inhomogeneous bodies of revolution (BOR) is presented. This method uses both surface- and volume-equivalence principles simultaneously, leading to a formulation of coupled integral equations of corresponding types. The computational examples are given for a free-space situation; however, a generalization into more sophisticated environments seems straightforward. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 44: 73–77, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20551

A hybrid symmetric FEM/MOM formulation applied to scattering by inhomogeneous bodies of revolution

A new symmetric formulation of the hybrid finite element method (HFEM) is described which combines elements of the electric field integral equation (EFIE) and the magnetic field integral equation (MFIE) for the exterior region along with the finite element solution for the interior region. The formulation is applied to scattering by inhomogeneous bodies of revolution. To avoid spurious modes in the interior region a combination of vector and nodal based finite elements are used. Integral equations in the exterior region are used to enforce the Sommerfeld radiation condition by matching both the tangential electric and magnetic fields between interior and exterior regions. Results from this symmetric formulation as well as formulations based solely on the EFIE or MFIE are compared to exact series solutions and integral equation solutions for a number of examples. The behaviors of the symmetric, EFIE, and MFIE solutions are examined at potential resonant frequencies of the interior and exterior regions, demonstrating the advantage of this symmetric formulation.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Diffraction from a locally inhomogeneous body of revolution by the method of secondary sources

Diffraction from a locally inhomogeneous body of revolution by the method of secondary sources

Electromagnetic scattering from axially inhomogeneous bodies of revolution

The electromagnetic scattering from partially or totally penetrable bodies of revolution (BOR) is formulated in terms of coupled Fredholm integral equations, solved by the method of moments (MM). The scatterers can have axial inhomogeneities, formed by dissimilar dielectric materials. The case of conducting bodies with axially discontinuous coatings is also treated. The penetrable regions can be lossy, characterized by complex permeability and permittivity. Boundary conditions are rigorously treated everywhere including the intersection of the various regions. The solutions are expressed in terms of combinations of two special matrices arising from the Galerkin technique. These solutions are implemented numerically for a class of generic axially inhomogeneous BOR scatterers. Numerical results given for various conducting/dielectric cylinder combinations using this formulation are compared with experimental data. For special cases where comparisons are possible, the present analysis replicates the results of the Mie theory.

Thermostress state of curvilinear orthotropic inhomogeneous bodies of revolution

Thermostress state of curvilinear orthotropic inhomogeneous bodies of revolution

The problem of the torsion of an inhomogeneous body of revolution with variable shear moduli

The problem of the torsion of an inhomogeneous body of revolution with variable shear moduli