The natural fit between metamaterials and radio frequency (RF) design was underscored early in the field, starting with the experimental demonstration of a metamaterial with a negative index-of-refraction in 2000, which was carried out at microwave frequencies (~10 cm wavelengths). At (relatively) low frequencies, the metals used to form the metamaterial circuits are good conductors that can form structures with relatively low absorption. Moreover, the large wavelengths associated with these frequencies-centimeters to meters, for example-allow a very simple process to be applied for patterning the metamaterial elements comprising the medium.
