A NOVEL-APPROACH IN CALCULATING V-I CURVES OF A DC-SQUID COUPLED TO APLANAR INPUT COIL

The influence of a planar input coil on the V-I characteristics of a d c-SQUID (superconducting quantum interference device) has been analyze d by means of computation and experimental investigation, An extended electrical model of the input coil based on transmission lines has bee n proposed. The frequency behavior of this model has been validated wi th an expanded copper model, The V-I characteristics of dc-SQUID's hav e been calculated with this extended circuit model using a SPICE-type circuit analysis program, The results have been compared with measurem ents of niobium dc-SQUID's, In this paper the relationship between the V-I characteristics of the SQUID and the coupling impedance of the wa sher is demonstrated.