Capacitor for signal propagation across ground plane boundaries in superconductor integrated circuits

摘要

The self inductance associated with a capacitance A52 in a superconductor integrated circuit (FIG. 1) is reduced by adding a layer of superconductor metal (A54) overlying the capacitor, effectively producing a negative inductance to counteract the self-inductance of the capacitor leads, thereby reducing inductance of the circuit. As a result it possible to transfer a single flux quantum ("SFQ") pulse through the capacitor. Capacitors (19 and 25 FIG. 5) of the foregoing type are incorporated in superconductor integrated circuit SFQ transmission lines (FIG. 5) to permit SQUID-to-SQUID transfer of SFQ pulses, while maintaining the circuit grounds of the respective SQUIDs in DC isolation. Bias current (10) may be supplied to multiple SQUIDs (1 & 3, 7 & 9 FIG. 5) serially, reducing the supply current required previously for operation of multiple SQUIDs.