Electrodynamics of materials with negative index of refraction

In the last several years, many efforts were spent in developing the new section of electrodynamics -electrodynamics of materials with negative index of refraction. The first experiments in this area [1, 2] were carried out by a group of physicists at the University of California, San Diego (UCSD, USA). These works demonstrated unusual electrodynamic properties of some composite materials. These characteristics can be formally explained if it is assumed that the given materials possess the negative index of refraction n. This material presents itself as a combination of small metallic elements, disposed in space in some geometric order, forming structure resembling a sort of crystal. It is possible to consider such a type of structure at wavelengths noticeably larger than the size of its elements and the distance between them. The experiments by the authors of the specified work were made in the centimeter range of wavelengths, but the sizes of the elements explored in the composites and the distances between elements are typically of the order of 7-10 mm.