This paper reviews several refraction methods of metamaterial. Metamaterial is an engineered structure to produce electromagnetic properties that is not naturally occurred in ordinary material, such as negative permittivity, negative permeability and negative refractive index. This reviewed paper focuses on negative refractive index application where complies with microwave and optical frequency ranges. Each method provides different frequency range. Split ring resonator used in microwave radiation enhances the gain while fishnet-chiral planar structure is used in photonic frequency. The photonic metamaterial acts similar to lens, which leads to enhancing the gain of the microwave.
