Isotropic Artificial Dielectric

Isotropic artificial dielectric media composed of a three-dimensional cubic array of metal or dielectric spheres have been investigated. Theoretical expressions using the Clausius-Mossotti relation have been derived for the index of refraction, dielectric constant, and magnetic permeability of this type of dielectric. These quantities are independent of frequency so long as the size of the spheres and the spacing between spheres are small compared to the wavelength within the resulting dielectric media. Samples using steel and fused-quartz spheres have been fabricated, and the dielectric properties measured in rectangular waveguide at a frequency of 5,000 megacycles per second. Standard waveguide techniques are readily adaptable to this type of dielectric. Experimentally determined values of the dielectric properties are in good agreement with theoretical values, and the theoretical expressions are assumed to be valid.