This paper presents an analytical and numerical investigation of the radiation features of an interesting class of electromagnetic bandgap (EBG) structures excited by an electric line source. The radiation from two-dimensional (2-D) lattices made with lossless dielectric cylinders, typically optimized by using the Bloch analysis of the corresponding 2-D photonic crystals, are originally investigated in terms of leaky waves. A thorough modal analysis of open waveguides, composed by a finite number of periodic chains of circular dielectric rods, is presented that shows a multiplicity of bound and leaky modes. Two radiation windows are identified and the relevant directive features are described in terms of properly excited dominant leaky modes. The possible excitation of higher order leaky modes and guided modes has been carefully considered, by also capturing the relevant residue contributions in a nonspectral representation of the excited fields. The final results on radiated fields by realistic truncated structures, obtained by ad-hoc software as well as full-wave EM simulators, are in excellent agreement with those predicted by the proposed leaky-wave approach.

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In this paper we present an efficient Matlab computation of a 3-D electromagnetic scattering problem, in which a plane wave impinges with a generic inclination onto a conducting ellipsoid of revolution. This solid is obtained by the rotation of an ellipse around one of its axes, which is also known as a spheroid. We have developed a fast and ad hoc code to solve the electromagnetic scattering problem, using spheroidal vector wave functions, which are special functions used to describe physical problems in which a prolate or oblate spheroidal reference system is considered. Numerical results are presented, both for TE and TM polarization of the incident wave, and are validated by a comparison with results obtained by a commercial electromagnetic simulator.

The scattering of a far-field source by perfectly conducting targets above a semi-infinite lossy medium is studied. An analytical solution is applied to the electromagnetic scattering problem with the Cylindrical Wave Approach. Interaction of a plane-wave field with the cylindrical targets is expressed through expansions into cylindrical waves, and a spectral approach is used to deal with the interaction of the scattered field and the interface. The method allows modelling the interaction of an external source with a biological medium, in the presence of external metallic objects. In the numerical examples, the electrical parameters of a muscle are used to model the biological tissue. Application to cases of interest for the total field transmitted in the muscle is investigated for both TM and TE polarization states. Penetration of the electromagnetic field is evaluated, both at the ISM frequency of 2.4 GHz and in the millimeter frequency range at 28 GHz.