Current Distribution and Nonlinearity of Open-Ends and Gaps in Superconducting Microstrip Structures

S. Mohammad Hassan Javadzadeh | Forouhar Farzaneh | Mehdi Fardmanesh

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URL :   http://research.shahed.ac.ir/WSR/WebPages/Report/PaperView.aspx?PaperID=137164
Date :  2012/12/28
Publish in :    Journal of Superconductivity and Novel Magnetism
DOI :  https://doi.org/10.1007/s10948-012-1989-z
Link :  http://dx.doi.org/10.1007/s10948-012-1989-z
Keywords :Intermodulation distortion, Microstrip discontinuities, Nonlinear modeling, Nonlinearity, Superconducting nonlinear effects

Abstract :

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Superconducting devices are known to produce nonlinear effects. In planar structures, these nonlinearities depend on the current distribution on the strip, which definitely depends on the structure of device. This paper used a numerical method based on 3D-FEM to obtain the current distribution in the open-ends and gaps in the superconducting microstrip structures. This is used to present the nonlinear distributed circuit modeling of these discontinuities and its impact on the nonlinear phenomenon. This nonlinear circuit model is used in the Harmonic Balance (HB) method to analyze nonlinearity in the superconducting microwave devices. Therefore, this simple accurate enough nonlinear circuit model is warmly welcomed to retire the seemingly inevitable use of time- and memory-consuming numerical techniques for nonlinear analysis of discontinuities in superconducting microwave structures. As an example, we analyze a microstrip superconducting end-coupled band pass filter (BPF). These results are very useful for optimizing the resonators of the superconducting microwave filters in order to minimize its nonlinear distortions.