Analysis of anisotropic high temperature superconductor planar structures on sapphire anisotropic substrates

A full-wave finite-difference time-domain technique is used to study the anisotropy associated with high temperature superconductor (HTS) planar structures. The analysis is performed on anisotropic YBCO film deposited on anisotropic sapphire substrate. The solution incorporates all the physical aspects of the HTS materials. The finite thickness of the anisotropic strip is rigorously modeled using a graded non uniform mesh generator. The propagation characteristics of HTS microstrip line are evaluated. The current distributions inside the HTS are calculated for both the normal and the super fluids. It is shown that the 90/spl deg/ r-cut sapphire substrate structure has lower loss and lower effective dielectric constant than the 0/spl deg/ r-cut substrate. Interesting aspects, concerning the anisotropy of HTS microwave structures, are presented.>