A brief review of metamaterials and their applications to antenna systems is given. Artificial magnetic conductors and electrically small radiating and scattering systems are emphasized. Single negative, double negative, and zero-index metamaterial systems are discussed as a means to manipulate their size, efficiency, bandwidth, and directivity characteristics.

We address, in this paper, the main features of hybrid modes propagating in a rectangular waveguide partially filled with pseudochiral Ω-slabs. For the particular case of a uniaxial Ω-slab, we show that LSE and LSM hybrid modes can propagate in this inhomogeneously filled rectangular waveguide. The influence of the Ω-parameter, which characterizes the magnetoelectric tensors of the bianisotropic slab, on LSM modes is analyzed--namely an increase in the bandwidth for monomodal operation is reported. In addition, a field displacement effect and a variable phase shift proportional to the change of the Ω-parameter are attained. Finally, it is shown that the propagation characteristics are independent of the direction of propagation and so, unlike the case of magnetically biased ferrite loading, reciprocal devices can be achieved.

The analysis of the shielding properties of chiral materials slabs is here presented, first deriving the spectral representation of the shielded fields, then getting the asymptotic expression of the transmission matrix in the higher frequencies. The time response of the shielded field for the NEMP incidence is finally deduced in a closed form.

The analysis of the shielding properties of a planar wire-mesh shield embedded in a general isotropic--chirality is included--or anisotropic stratified media is here presented. A suitable model of the grating has been introduced in order to consider the occuring phenomena, in fact through a spectral technique the electromagnetic problem is translated into the equivalent circuit network model that allows to express the time response of the shielded field for the NEMP incidence in a closed form.