Analysis and Simulation of Distributed Nonlinearities in Ferroelectrics and Superconductors for Microwave Applications

Abstract—This paper gives closed-form equations for the inter-modulation and third harmonic signals generated in a nonlinear transmission line with distributed quadratic nonlinearities in the conductor and dielectric. Although the formulation developed is general, it is intended to be used in planar devices combining high-temperature superconductor (HTS) and oxide ferroelectrics. The analysis in this paper shows that the intermodulation and third harmonic signals produced by an HTS tend to cancel those of a fer-roelectric, and that full cancellation is theoretically possible. This opens the way for using HTS/ferroelectric multilayers, not (only) for their tunable or phase-shifting properties, but for highly linear spurious-free planar HTS devices. Index Terms—Ferroelectric, high-temperature superconductor (HTS), intermodulation distortion (IMD), nonlinear transmission line (NLTL), nonlinearities, superconductor. I