Electromagnetic scattering from cylindrical objects above a conductive surface using a hybrid finite-element–surface integral equation method

Abstract

This work presents a novel finite-element solution to the problem of scattering from a finite and an infinite array of cylindrical objects with arbitrary shapes and materials over perfectly conducting ground planes. The formulation is based on using the surface integral equation with Green's function of the first or second kind as a boundary constraint. The solution region is divided into interior regions containing the cylindrical objects and the region exterior to all the objects. The finite-element formulation is applied inside the interior regions to derive a linear system of equations associated with nodal field values. Using two-boundary formulation, the surface integral equation is then applied at the truncation boundary as a boundary constraint to connect nodes on the boundaries to interior nodes. The technique presented here is highly efficient in terms of computing resources, versatile, and accurate in comparison with previously published methods. The near and far fields are generated for a finite and an infinite array of objects. While the surface integral equation in combination with the finite-element method was applied before to the problem of scattering from objects in free space, the application of the method to the important problem of scattering from objects above infinite flat ground planes is presented here for the first time, to our knowledge.

An Efficient Multiregion FEM-BIM for Composite Scattering From an Arbitrary Dielectric Target Above Dielectric Rough Sea Surfaces

“…3(b) gives the field distribution along the boundary. With the results compared with those of the traditional FEM-BIM [20], it can be seen that the results of the multiregion FEM-BIM show good agreement with those of the traditional FEM-BIM. The relative error of the multiregion Fig.…”

“…In (20), the interactions from subordinate regions S 1l and S 1r are taken into account as a second incident source. As the secondary incident wave, the total incident field impinged in the dominant regions can be received by substituting (18) and (19) into (21).…”

“…A hybrid finite-element-surface-integralequation method [20] was presented by Alavikia and Ramahi to study electromagnetic scattering from cylindrical objects above a conductive plane surface. Demarcke and Rogier [21] applied the Poincare-Steklov operator notation to provide substantial theoretical insight into the analysis of spurious solutions in hybrid finite-element-boundary-integral-equation formulations to predict the breakdown frequencies of different hybrid formulations.…”

Application of FEM-BIE for scattering from dielectric objects buried under a rough surface

“…(1) with a G , integrating over a Ω , and invoking the second Green's scalar theorem (6) where b k is the wave number of b Ω . The Green's function…”

“…However, the approximate absorbing boundaries often need to be set far enough away from the model surface to keep their precision, and are often invalid to some particular problems. To improve the precision and the versatile of FEM, the boundary integral equation [5,6] is introduce as the artificial truncated boundary. The earlier work based on FEM always used an artificial boundary to enclose the whole scattering model, which consumes largely of computational time and memory.…”