Artificial dielectrics

Artificial dielectrics are fabricated electromagnetic materials consisting of synthetic substances, usually constructed in an orderly arrangement, such as arrays. The arranged materials, and the distances between them are usually evenly spaced on, or within, a substrate. Hence, the arrays of inclusions are in a periodic or lattice structure. Also, the lattice spacing is smaller than the impinging electromagnetic wavelength. 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.