Metamaterials possess unusual properties, such as negative permeability and permittivity. Metamaterials can be implemented using periodic structures, made of conductors and dielectrics, with a period smaller than tenth of the wavelength. The form of the unit cell and its periodicity determine the material properties as a function of frequency.
Metamaterials, and other periodic structures, enable to design different devices in microwave frequency range with special performance and improve the performance of existing devices. For example: reduction of the mutual coupling between printed antennas, miniaturization of antennas and microwave devises, design of planar lenses, symmetrical objects with enhanced monostatic radar cross section (RCS), artificial magnetic conductor (AMC) for low-profile antennas and reduced monostatic RCS platforms, frequency selective surface (FSS) radomes, low-profile absorbing materials, etc.