2020/03/31 by S. Mahashabde, Sumedh Mahashabde, Ernst Otto +9 · 53 citations
Physics and Astronomy · #Advanced Frequency and Time Standards #Coupling (piping) #Coupling coefficient of resonators #Electrical impedance #Inductance #Microwave #Physics of Superconductivity and Magnetism #Planar #Resonator #Superconducting and THz Device Technology #Superconductivity #Tuning fork #cond-mat.supr-con #physics.app-ph
paper · pdf · doi:10.1103/physrevapplied.14.044040
published in Physical Review Applied 14(4) (American Physical Society)
openalex created_date 2020/04/03 · arxiv created 2020/05/02 · openalex publication_date 2020/10/21 · arxiv updated 2020/10/28 · openalex updated_date 2026/08/05
We present fast tunable superconducting microwave resonators fabricated from planar NbN on a sapphire substrate. The 3\ensuremathλ/4 wavelength resonators are tuning fork shaped and tuned by passing a dc current that controls the kinetic inductance of the tuning fork prongs. The \ensuremathλ/4 section from the open end operates as an integrated impedance converter that creates a nearly perfect short for microwave currents at the dc terminal coupling points, thus preventing microwave energy leakage through the dc lines. We measure an internal quality factor Qint>105 over the entire tuning range. We demonstrate a tuning range of greater than 3% and tuning response times as short as 20 ns for the maximum achievable detuning. Because of the quasifractal design, the resonators are resilient to magnetic fields of up to 0.5 T.