Effects of the Design Parameters on Characteristics of the Inductances and JJs in HTS RSFQ Circuits

We have investigated various geometrical design dependencies for rapid single-flux-quantum (RSFQ) circuits in high-T
_c
superconductors (HTS) technology, including the characteristics of the intermediate inductances. Structural- and temporal-dependent combinations of C
_n
-R
_n
(capacitance and normal resistance of the Josephson junctions, JJs) in the HTS technology are also investigated. Relatively favorable combinations of normal resistance and low capacitance of the JJs needed in the HTS technology for RSFQ circuits have been made possible by recent fabrication methods of high-quality YBCO films. Obtaining these devices is made achievable by using the grain boundary structures and high critical current density (JC) of the HTS JJs. Mutual interactions of the intermediate inductances with other parts of the whole circuit are examined and optimized for the best operation situation. Here in particular, the operation of the HTS Josephson transmission-line (JTL) cells utilizing the grain boundary Josephson junctions, including various structural inductances, is studied based on the reported parameters of the developed devices and thoroughly analyzed by simulation results.