Spectral response and far-field pattern of a dipole nano-antenna on metamaterial substrates having near-zero and negative indices of refraction

► The metamaterial is modelled as an homogeneous material having an equivalent index of refraction. ► The resonant wavelength of a dipole nano-antenna do not depend on the sign of the equivalent refraction index. ► The resonant wavelength reaches a minimun when the equivalent index approaches to zero. ► The response is maximum when the equivalent index of refraction approaches to zero. ► The far-field pattern do not depend on the sign of the equivalent index of refraction.