Analysis of dielectric-loaded cavities for characterization of the nonlinear properties of high temperature superconductors

Abstract

Abstract-This work describes and compares two alternative methods of analyzing dielectric-loaded cavities for measurement of intermodulation distortion in HTS films. One of them is based on assuming a specific type of HTS nonlinearities and developing theoretical equations based on them. The second is based on a numerical approach that can be applied to many types of nonlinearities. Both methods are shown to work on measured data of representative HTS films.

Analysis and Simulation of the Effects of Distributed Nonlinearities in Microwave Superconducting Devices

“…The equivalent voltages and currents of these spectral components have to match the linear problem, and they are iteratively adjusted until they do. As shown in [48], the agreement between the closed-form (40) or (41) and HB is very good throughout the whole range of source powers which is likely to be used in IMD measurements of these cavities.…”

“…To find the intermodulation and third-harmonic currents in the transmission line, we start by combining (20) and (21) to obtain a time domain equation for (48) which, at a given frequency , can be written as (49) where and are the Fourier transforms of and at and , are the propagation constant and characteristic impedance of the line at that frequency, i.e., (50) (51)…”