Artificial dielectrics are artificial electromagnetic materials consisting of arrayed, synthetic substances. The arrays themselves, and the distances between synthetic substances are usually evenly spaced on, or within, a substrate. Hence, the arrays of inclusions are in a periodic or lattice structure. The lattice spacing is smaller than the impinging electromagnetic wavelength of interest. These were first conceptualized, constructed and deployed for interaction in the microwave frequency range in the 1940s and 1950s. The constructed medium, the artificial dielectric, has an effective permittivity and effective permeability, as intended.
In addition, some artificial dielectrics may consist of irregular lattices, random mixtures, or a non-uniform concentration of particles.