Bi-SQUID Versus dc SQUID in Flux-Driven Traveling-Wave Parametric Amplifier

Characteristics of artificial waveguide lines composed of finite-size artificial cells are analyzed and discussed with relation to designing traveling-wave parametric amplifiers. From this point of view, the flux-driven amplifier suggested recently can be considered as the most successful amplifier design. To increase dynamic range of the amplifier, dc SQUID cells of the artificial line in use can be substituted for bi-SQUID cells. The 1 dB compression points of the amplifier gain are calculated and compared for both types of cells.