  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.
