Optimization of High Tc Superconducting Microwave Planar Structures

This paper compares the characteristics of superconducting microstrip lines to those of inverted microstrip line with the aim of obtaining the optimal structure that suits certain applications. Characteristics of two high Tc superconducting planar structures on LaA103 are evaluated using a two-dimensional numerical code based on the two fluid model and the TMz mode solution. The losses in the superconducting strip as well as the dielectric losses are taken into consideration. Three structures of the same characteristic impedance are considered. It is shown that the inverted microstrip line has a more uniform current and magnetic flux-density distributions, and lower dielectric and conductor losses, which makes it well suited for high current transmission. Although the microstrip line has more dielectric and conductor losses, it has a higher Q factor due to the large energy stored in the dielectric substrate.