Electrically isotropic artificial dielectrics from a realizable and easily engineered physically anisotropic particle

An electrically isotropic yet physically anisotropic particle has been developed that can be realized with currently available prototyping and manufacturing capability. The effective permittivity was found to be significantly sensitive to x-direction or y-direction changes in the particle dimensions. Within a reasonable degree of accuracy, the effective permittivity of an infinite cubic lattice of this electrically cube-like particle can be easily engineered with the 3D Maxwell Garnett formula. Further, an empirical yet convenient formula for the effective volume fraction of the particle gives significantly improved accuracy when used in the 3D Maxwell Garnett formula. The design procedure employed is easily adaptable to the realization of similar 3D particles where the number of dielectric and metallic layers as well as their thickness may differ from that which was considered in this work. Such electrically cube-like particles can be used to selectively enhance the background permittivity of planer substrates by as much as a factor of five and may therefore find useful application in miniaturization of planar antennas and microwave circuits.