Computer simulation of a voltage standard using multiple Josephson junctions

A multiple junction voltage cell has been computer modeled to test its freedom from spurious internal oscillations and its tolerance to process variations during fabrication. This multiple junction cell model consists of two Josephson junctions coupled together through realistic circuit elements and tied to an external RF source by means of a resistive stripline. Process variations are modeled by varying the values of the shunting resistors and the critical currents of the junctions. This modeling shows stability for the multiple cell structure under realistic circuit values and parameter variances. Resistor variances (peak-to-peak variation) of plus and minus 30 percent still allow a constant voltage step to superimpose across the multiple junction standard. Critical current variances are even less degrading than resistor variances.