C. Athanasiadis

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A spherical acoustic wave is scattered by a bounded obstacle. A generalization of the ‘optical theorem’ (which relates the scattering cross-section to the far-field pattern in the forward direction for an incident plane wave) is proved. For a spherical scatterer, lowfrequency results are obtained by approximating the known exact solution (separation of(More)
Time-harmonic electromagnetic waves are scattered by a homogeneous chiral obstacle. The corresponding transmission problem is reduced to a pair of coupled integral equations over S, where S is the interface between the obstacle and the surrounding medium. This is done using a generalization of the Stratton–Chu representation that is valid for chiral media.(More)
A spherical electromagnetic wave is scattered by a bounded perfectly conducting obstacle. A generalization of the plane-wave optical theorem is established. For a spherical scatterer, low frequency results are obtained by approximating the known exact solution (separation of variables). In particular, a closed-form approximation of the scattered wavefield(More)
Time-harmonic electromagnetic waves are scattered by a homogeneous chiral obstacle. The reciprocity principle, the basic scattering theorem and an optical theorem are proved. These results are used to prove that if the chirality measure of the obstacle is real, then the far-"eld operator is normal. Moreover, it is shown that the eigenvalues of the far-"eld(More)
A spherical acoustic wave is scattered by a three layered sphere with a soft core. Exact expressions of the fields in every layer and the exterior of the scatterer are established. Low frequency results are then obtained by approximating the exact expression of the scattering cross section. The inverse problem of determining the sphere's center and the(More)
A layered scatterer with a soft or hard core is excited by a time harmonic spherical acoustic wave, generated by a point source located in the interior of the scatterer. Reciprocity and general scattering relations are established, relating the total, primary and secondary fields with the corresponding far field patterns. Moreover, we formulate the optical(More)
The problem of scattering of spherical electromagnetic waves by a bounded chiral obstacle is considered. General scattering theorems, relating the far–field patterns due to scattering of waves from a point source put in any two different locations (the reciprocity principle, the optical theorem, etc), and mixed scattering relations (relating the scattered(More)
A spherical electromagnetic wave is scattered by a layered sphere with a perfect electric conducting core. Low frequency results are obtained by approximating the known exact expressions of the scattering cross section. The inverse problem of determining the sphere's center and the layers radii and materials is treated from the knowledge of the leading(More)
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