Directive scattering by a line source coupled to infinite or finite Electromagnetic Band-Gap media

Radiation from a line source coupled to an Electromagnetic Band-Gap material is analyzed with two different methods. Using lattice sums technique combined with generalized reflection matrix method, the scattering from a crystal of infinite extension is rigorously investigated. The radiation from an electromagnetic crystal of finite extension is also solved with Cylindrical Wave Approach. The two methods show perfect agreement when the source is localized within the crystal, achieving a directive radiation. As a spacing between the two Electromagnetic Band-Gap layers is introduced, the finite structure analyzed with the Cylindrical Wave Approach shows significant edge diffraction at the boundaries. Agreement between results from the methods is recovered introducing a suitable layout of absorbers in the cavity