Introduction Brief description on definition of electromagnetic metamaterialsElectromagnetic (EM) Metamaterials have specific EM properties that cannot be found in nature (Caloz & Itoh, 2006). These specific EM properties are obtained by the artificial structures, rather than the composition of the metamaterials, and affect the propagations of EM waves when the average structure sizes are much smaller than the guided wavelengths g , i.e., at least smaller than g /4. Since the propagation of an EM wave is related to its electric and magnetic fields, the EM properties of Electromagnetic (EM) Metamaterials can be described by using its permittivity ε and permeability .