Periodic Superconducting Microstrip Line With Nonlinear Kinetic Inductance

This paper investigates linear and nonlinear microwave propagation in a periodic superconductor-normal conductor microstrip transmission line (S-N muTL). We derive closed-form equations for complex propagation constant, input impedance and complex resonant frequencies for linear infinite and finite periodic S-N muTL. Jumps on the curves of attenuation constants, input impedances and eigenfrequencies occur exactly at the Bragg frequencies. We demonstrate that the finite S-N muTL shows the same behavior as infinite periodic SmuTL, when there is enough number of unit cells. Furthermore, nonlinear microwave signal propagation analyses are carried out based on the self-consistent method, when the kinetic inductance of the superconducting segments is in the nonlinear regime.