Wideband Nonlinear Response of High Temperature Superconductor Thin Films From Transmission-Line Measurements
Jordi Mateu, James Booth, Brian H. Moeckly
We report on a technique for extracting an accurate value of the nonlinear inductance DL(i) in superconducting transmission lines. The novelty of this technique is to assess the frequency dependence of the transmission line nonlinear response. A wideband nonlinear measurement system was used to simultaneously measure the third-order spurious signals at 2f1-f2, 2f2-f1, 2f1+f2, 2f2+f1, 3f1 and 3f2 frequencies. Measurements for different values of the fundamental frequencies f1 and f2 allows us to study the spurious signal generation from 1 GHz to 21 GHz. We demonstrate this technique by measuring several superconducting YBa2Cu3O7-x coplanar waveguide transmission line geometries, patterned in a single chip, at 80 K. The results show a linear frequency dependence of the nonlinear response, indicating a dominant contribution of the nonlinear inductance over the nonlinear resistance, wDL(i)>>DR(i). The experimentally obtained nonlinear inductances are then used for determining device-independent measures of the linearity of the thin-film material in order to provide the foundation for modeling the nonlinear response of specific devices.
, Booth, J.
and Moeckly, B.
Wideband Nonlinear Response of High Temperature Superconductor Thin Films From Transmission-Line Measurements, IEEE-MTT-S International Microwave Symposium, Honolulu, HI, USA
(Accessed June 9, 2023)