Scattering Analysis from Lossy Dielectric Cylinder Buried in a Dielectric Half-space Using the Extended Method of Auxiliary Sources

The scattering of a transverse magnetic (TM) plane wave by a dielectric cylinder buried in a dielectric half-space is solved by the extended method of auxiliary sources (EMAS). In order to approximate the electromagnetic fields in each domain according to the EMAS, fictitious current sources satisfying the Helmoltz equation for each considered domain, are introduced and distributed around each physical boundary. To model the strong coupling affecting the structure, four bases of auxiliary sources have to be selected and spread in such way to satisfy the boundary conditions between the dielectric cylinder, the dielectric half-space, and the upper free space: two bases for the filled dielectric and the others around the air-half-space boundary. The standard impedance boundary conditions (SIBC) lead to a linear system from which we easily deduce the magnitude and the phase of the unknown currents. Hence, the scattered field is determined as a function of these currents. To validate the accuracy of the EMAS, numerical experiment was carried out for two cylinders, one a perfectly electric conductor (PEC) and the other with a lossy dielectric. For a TM incidence, their backscattering radar cross-sections, have been calculated and the results are in good agreement with the literature.