Experimental Study of Harmonic Mixer Using two HTS YBCO Grain Boundary Josephson Junctions in Series

• Published in: 2019 44th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) pp. 1 - 2
• Main Authors: Yu, M., Geng, H. F., Hua, T., Xu, W. W., Chen, Z. N., Shi, J. X., Wang, H. B., Chen, J., Wu, P. H.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01.09.2019
• Subjects: Critical current density (superconductivity); Harmonic analysis; Josephson junctions; Junctions; Mixers; Yttrium barium copper oxide
• ISSN: 2162-2035
• DOI: 10.1109/IRMMW-THz.2019.8873883

Two high-Tc superconducting (HTS) YBa 2 Cu 3 O 7-δ (YBCO) grain boundary (GB) Josephson junctions in series as a harmonic mixer is investigated. The research shows that the mixer consisting of two series YBCO Josephson junctions has a larger harmonic number than that with only one junction in heterodyne mixing at zero-voltage bias. One of the advantages of the series-Josephson-junction mixer is that the total critical current is improved without sacrificing the sensitivity of the junctions in the array that makes the mixer easier to get more microwave induced-steps required by larger harmonic number. Furthermore, the underdamped YBCO GB series-Josephson-junction mixer operated at zero-bias voltage, where the zero-order Shapiro step exists, achieves mutual phase locking of the junctions in the array, resulting in an excellent mixing performance. Thus, the series-underdamp-Josephson-junction mixer with zero bias is predominant and compact in terahertz (THz) application due to its excellent performance and no dc bias supply.