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Superconducting Thin-Film Transformers at Microwave Frequencies



A. H. Miklich, J. X. Przybysz, T. J. Smith, Samuel Benz, Todd E. Harvey


We describe the use of thin-film superconducting transformers at frequencies up to 20 GHz. Transformers with turns ratios of 2,3, and 7 were fabricated out of Nb and tested in a liquid-He Dewar. The measured S-parameters showed considerably less bandwidth than predicted based on a consideration of the lumped-element inductances of the circuit elements. We present an alternative model for the transformer where each part of the patterned circuit is treated as a distributed element (a transmission line). Despite the simplicity of the model, simulations using it agree well with the measured data without using any fitted parameters. These simulations take only a few minutes to compute on a typical workstation, making the model well suited as a design tool.
IEEE Transactions on Applied Superconductivity


microwave, superconducting, transformer, transmission line


Miklich, A. , Przybysz, J. , Smith, T. , Benz, S. and Harvey, T. (1999), Superconducting Thin-Film Transformers at Microwave Frequencies, IEEE Transactions on Applied Superconductivity (Accessed December 7, 2023)
Created May 31, 1999, Updated October 12, 2021