Cases of electromagnetic wave propagation in a complex medium

The problem of how to differentiate between left-handed material and right-handed material has been analyzed in detail. The results show that the imaginary parts of permittivity and permeability will influence the sign of refractive index when the real parts of permittivity and permeability are opposite signs. Similarly, the real parts of permittivity and permeability will influence the variation of the amplitudes when the imaginary parts of permittivity and permeability are opposite signs. Therefore, it may has other choices to study the negative refraction except the double negative medium, and there should be some extra properties that can be related to the specific properties of the new materials.