The Renormalization Effects in the Microstrip-SQUID Amplifier
  The peculiarities of the microstrip-DC SQUID amplifier caused by the resonant structure of the input circuit are analyzed. It is shown that the mutual inductance, that couples the input circuit and the SQUID loop, depends on the frequency of electromagnetic field. The renormalization of the SQUID parameters due to the screening effect of the input circuit vanishes when the Josephson frequency is much greater than the signal frequency. 
G. P. Berman, A. A. Chumak, and V. I. Tsifrinovich
quant-ph cond-mat.supr-con