Fast digital phase shifter based on S-N transition in high-Tc superconducting film

The phase shifters with Δϕ = 11° and 45° based on S-N transition in high-Tc superconducting films were simulated and experimentally investigated. The S-N switching elements in single-strip and double-strip form were used. A fast phase shift pulse response to the short control current pulse was observed. Dependence of transient time on control current has been detected; the more is the current, the shorter is the time of a transition from the superconducting to the normal state. The fall time depends on the thermal conductivity of a substrate and in the case of sapphire substrate is about tenth nsec.