Characteristic Impedance Design Considerations for a High-Speed Superconducting Packaging System (Short Papers)

The characteristic impedance influences of superconducting packaging systems (in particular, Josephson packaging) on the degradation in transmitted signal rise time, amplitude distortions and crosstalk, signal propagation delay, and amplitude decay at the inductive and resistive connectors with matched capacitors are quantitatively evaluated by using the ASTAP computer simulation. The present choice of the characteristic impedance Z₀ = 10- 12 Omega for a superconducting stripline is inadequate. Higher impedances of Z₀=40-50 Omega are useful from the standpoint of noise performance improvement. At the same time, a higher impedance choice can make the ground connector numbers of each connector decrease, which is preferable for a large-scale packaging system.