High-Temperature Superconducting Nonlinear Transmission Lines

This paper introduces novel potential device applications based on the nonlinear phase shifting properties of high-temperature superconductor (HTS) transmission lines. It demonstrates how the nonlinear characteristics of HTS materials can be used to build devices that improve the risetime of pulses as well as exhibit power-dependent phase shifting properties. The nonlinear transmission-line circuit layouts consist of a linear transmission-line periodically loaded with HTS stubs operating in the nonlinear region. Theoretical results are presented using a lumped-element SPICE model to verify the pulse-shaping concept presented in this paper. The power-dependent phase shifting properties are demonstrated with the measurements of two prototype circuits. Index Terms--High-temperature superconductor (HTS), nonlinear transmission line (NLTL), pulse sharpening, risetime improvement, power-dependent phase shifter, shockline.