Impedance matching of an rf SQUID to a standard transmission line

The rf SQUID resolution is known to be dependent on the pump frequency. For the vhf range and above, the classical rf high impedance circuit is not directly applicable and a "matched" configuration is necessary requiring suitable transmission line. We present a theoretical study of the SQUID matched to a standard fifty Ohms line and five optimization rules for obtaining the best resolution. The noise has been introduced first as a narrow-band source coming from the preamplifier and secondly completed by broad band contribution. Both theoretical and experimental results are presented demonstrating the usefulness of the model.