Design and analysis of high-T/sub c/ SQUID current amplifiers

SQUID preamplifiers are very sensitive and have a low noise level. We present simulation studies for asymmetric voltage biased SQUID current amplifiers with one superconducting layer. For a simple SQUID amplifier the gain has been calculated versus the loop and noise parameter. An optimum of the gain versus the loop parameter has been obtained. For a parallel SQUID array amplifier a design rule has been derived. The possible margins for the critical current have been calculated. The inductance values used in the simulations have been calculated by a 3D field program from an assumed layout.