Scattering by buried dielectric cylindrical structures M. Di Vico Dipartimento di Elettronica Applicata, Universita ` degli Studi Roma Tre, Rome, Italy F. Frezza Dipartimento d’Ingegneria Elettronica, Universita ` degli Studi La Sapienza di Roma, Rome, Italy L. Pajewski and G. Schettini Dipartimento di Elettronica Applicata, Universita ` degli Studi Roma Tre, Rome, Italy Received 29 September 2004; revised 22 February 2005; accepted 25 April 2005; published 25 August 2005. [1] An analytical-numerical technique for the solution of the two-dimensional electromagnetic plane wave scattering by a finite set of dielectric circular cylinders buried in a dielectric half-space is presented. The problem is solved for both the near- and far-field regions, for transverse magnetic and transverse electric polarizations. The scattered field is represented in terms of a superposition of cylindrical waves, and use is made of the plane wave spectrum to take into account the reflection and transmission of such waves by the interface. The validity of the approach is confirmed by comparisons with results available in the literature, with very good agreement, and by self-consistency tests. Applications of the method to objects of arbitrary cross section simulated by suitable configurations of circular cylinders are shown. Citation: Di Vico, M., F. Frezza, L. Pajewski, and G. Schettini (2005), Scattering by buried dielectric cylindrical structures, Radio Sci., 40, RS6S18, doi:10.1029/2004RS003182. 1. Introduction [2] The two-dimensional scattering problem of elec- tromagnetic waves by buried cylindrical objects has wide application in remote sensing of buried pipes, conduits and cables, in the understanding of mutual interactions between buried objects and surrounding media, in the communication through the earth, in the backscattering from randomly distributed scatterers. For this reason, such problem has been discussed by many authors in the past, both from a theoretical and a numerical point of view, and several different techniques have been proposed to solve it. [3] Howard [1972] solved a two-dimensional Fred- holm integral equation for the scattered field from a subterranean cylindrical inhomogeneity excited by a line source employing an eigenfunction expansion. In the pioneering analytical work [D’Yakonov , 1959], an inter- esting solution is obtained as a limiting case of a boundary value problem involving two nonconcentric cylinders, but the results are not suitable for numerical evaluation. D’Yakonov’s work is extended by Ogunade [1981] in a form appropriate for obtaining numerical data, using conventional eigenfunction expansions; the author considered a conducting circular cylinder inside a dielectric cylinder and took the limit that the radius of the dielectric cylinder goes to infinity; therefore his results cannot be extended to arbitrary configurations and cross sections. Budko and van den Berg [1999] modeled a finite-sized object embedded in a lossy half-space in terms of an effective homogeneous circular scatterer, and a Green’s function approximate approach is employed. Bertoncini et al. [2001] applied the uniform geometrical theory of diffraction to calculate the scattering from a polygonal perfectly conducting object buried in a lossy half-space. [4] Ellis and Peden [1995] computed the scattering from buried inhomogeneous dielectric objects, in the presence of an air-earth interface, employing a two- dimensional method of moment formulation and utilizing cylindrical pulse basis functions and point matching. Surface integral equation methods have been used to treat a buried dielectric cylinder by Butler and Xu [1989] and Diamandi and Sahalos [1991]. Volume integral equation methods have been used for determining the scattering from a two-dimensional buried lossy dielectric RADIO SCIENCE, VOL. 40, RS6S18, doi:10.1029/2004RS003182, 2005 Copyright 2005 by the American Geophysical Union. 0048-6604/05/2004RS003182$11.00 RS6S18 1 of 11