arXiv subjects

Ehsan Khodapanah

Publications and source records attributed to Ehsan Khodapanah.

3 recordsLinked to original sources

arXiv2019

An FE-EBC Method for Electromagnetic Scattering from Inhomogeneous Objects

In this paper, we present a finite-element-extended boundary condition (FE-EBC) method for an efficient calculation of the electromagnetic wave scattering from inhomogeneous magneto-dielectric objects. To this end, we apply the hierarchical Legendre polynomial basis functions on large curved inhomogeneous hexahedral elements and propose an efficient numerical algorithm for a fast computation of the finite-element matrix entries in the presence of the material and Jacobian inhomogeneities. Also, we present a multiple-harmonic expansion on the surface boundary to represent the surface magnetic field accurately. The accuracy, efficiency and convergence of the method are studied through some numerical examples.

physics.comp-ph↗

arXiv2017

A Product to Sum Approach for Matrix Filling in a Hierarchical Finite-Element Method

This paper presents a product to sum approach for a fast and efficient matrix filling in a hierarchical finite-element method (FEM). Due to the existence of a coupling factor arising from the material and Jacobian inhomogeneities in curved inhomogeneous elements, the calculation of the FEM matrix elements should be carried out through full multidimensional integrations. This reduces the efficiency of the higher order FEM solvers especially when the coupling factor varies rapidly inside the elements. In the product to sum approach, every product of the basis and weighting polynomials is replaced with a sum of appropriate polynomials. This reduces the number of required multidimensional integrals significantly and converts the integration into a summation. Therefore, the method will be efficient if the number of summation terms in the product to sum conversion is as small as possible.

math.NA↗

arXiv2016

A Jacobian Separable 2-D Finite-Element Method for Electromagnetic Waveguide Problems

We propose an efficient finite-element analysis of the vector wave equation in a class of relatively general curved polygons. The proposed method is suitable for an accurate and efficient calculation of the propagation constants of waveguides filled with pieces of homogeneous materials. To apply the method, we first decompose the 2-D problem domain into a set of curved polygons of a specific characteristic. Then we divide every polygon into a set of triangular elements with two straight edges. Finally, we introduce a set of hierarchical mixed-order curl-conforming vector basis functions inside every triangular element to discretize the vector wave equation. The advantages of the method are as follows. The curved boundaries of the elements are modeled exactly and hence there is no approximation in the geometrical modeling. 2-D integrals of the matrix elements are reduced to 1-D integrals. Therefore, the matrix filling can be performed very fast. Total number of elements due to the discretization of a given domain is very small, and hence the discretization of the problem domain takes up a very small percentage of the total computational time. We validate the method by comparing the results with those of Ansoft HFSS simulator and investigate the accuracy and efficiency of the method through some numerical examples.

physics.comp-ph↗