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This article describes a procedure for the calculation of the intermodulation behavior of the TM010 mode in high temperature superconducting (HTS) disk resonators from a description of the local HTS nonlinearities. Successful cross-checks are performed by comparing the theoretical results with experimental measurements and simulations based on the multiport harmonic balance algorithm for a specific model of HTS nonlinearity. The application of this procedure to the determination of nonlinear material parameters from disk resonator measurements is illustrated and compared to theoretical predictions.

This work describes a simulation tool being developed at UPC to predict the microwave nonlinear behavior of planar superconducting structures with very few restrictions on the geometry of the planar layout. The software is intended to be applicable to most structures used in planar HTS circuits, including line, patch, and quasi-lumped microstrip resonators. The tool combines Method of Moments (MoM) algorithms for general electromagnetic simulation with Harmonic Balance algorithms to take into account the nonlinearities in the HTS material. The Method of Moments code is based on discretization of the Electric Field Integral Equation in Rao, Wilton and Glisson Basis Functions. The multilayer dyadic Green's function is used with Sommerfeld integral formulation. The Harmonic Balance algorithm has been adapted to this application where the nonlinearity is distributed and where compatibility with the MoM algorithm is required. Tests of the algorithm in TM010 disk resonators agree with closed-form equations for both the fundamental and third-order intermodulation currents. Simulations of hairpin resonators show good qualitative agreement with previously published results, but it is found that a finer meshing would be necessary to get correct quantitative results. Possible improvements are suggested.

A procedure for the numerical prediction of the microwave nonlinear behavior (intermodulation products, degradation of quality factors, etc.) of TM010 disk resonators has been developed. The procedure is based on relating a very general description of HTS nonlinearities with the circuit elements of a nonlinear radial transmission line. This radial transmission line is then analyzed using the harmonic balance algorithm. Successful cross-checks are performed by comparing simulations with theoretical results obtained for a specific model of HTS nonlinearity. The application of this procedure to the determination of nonlinear material parameters from disk resonator measurements is illustrated as well as its use for simulating filters with several inter-coupled disks. Correction: J. Mateu, IEEE Trans. Appl. Superconduct., vol. 11, pp. 135–138, Mar. 2001. On p. 137 of the above paper, the first sentence of the paragraph immediately following equation (14) should read as follows.

This work presents the use of Harmonic Balance to simulate the nonlinear behavior of HTS transmission lines. Good agreement with theoretical cross-checks is found. We also show the use of this algorithm to fit the model of HTS lines from experimental measurements. We illustrate this by fitting several types of experimental data, and discuss how to avoid ambiguity in this fitting.

We present the design of a Y-Ba-Cu-O on LiNbO/sub 3/ cryogenic electro-optical modulator for analog 2 GHz applications. A resonant configuration of coplanar electrodes is considered, showing improvements with respect to both resonant Au electrodes and to traveling-wave electrodes, even beyond the traveling-wave theoretical maximum performance limit. The optimized layout is presented featuring a reduced length of 8.26 mm.

A procedure for the numerical prediction of the microwave nonlinear behavior (intermodulation products, degradation of quality factors, etc.) of TM010 disk resonators has been developed. The procedure is based on relating a very general description of HTS nonlinearities with the circuit elements of a nonlinear radial transmission line. This radial transmission line is then analyzed using the harmonic balance algorithm. Successful cross-checks are performed by comparing simulations with theoretical results obtained for a specific model of HTS nonlinearity. The application of this procedure to the determination of nonlinear material parameters from disk resonator measurements is illustrated as well as its use for simulating filters with several inter-coupled disks.

This paper describes the application of Harmonic Balance algorithms to predict nonlinear effects in planar High Temperature Superconductors (HTS) microwave circuits. The resulting algorithms are fast and efficient and can be used both for the characterization of the nonlinearities in the HTS material, and for the prediction of the behavior of an HTS circuit given the parameters of these nonlinearities (such as a dependence of the surface impedance on the current density). Most previously published nonlinear HTS models can be used, because the algorithms are not restricted to a specific model of HTS nonlinearities. Two different types of algorithms are described: (1) algorithms specific for one-dimensional resonators (transmission lines and TM010 disk resonators) and (2) an algorithm based on the combination of Method of Moments and Harmonic Balance, applicable to 2D planar structures with few restrictions in their shape. Several cross-checks with theory and measurements are presented.

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.