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Vacuum-Gap Capacitors for Low-Loss Superconducting Resonant Circuits



Katarina Cicak, Michael S. Allman, Joshua Strong, Kevin Osborn, Raymond W. Simmonds


Low-loss microwave components are used in many superconducting resonant circuits from multiplexed readouts of low-temperature detector arrays to quantum bits. Two-level system (TLS) defects in amorphous dielectric materials cause excess energy loss. In an effort to improve capacitor components we have used optical lithography and micromachining techniques to develop superconducting parallel-plate capacitors without lossy dielectrics. Resonance measurements on lumped LC-circuits that incorporate these capacitors reveal significantly lower loss-tangents at mK temperatures than with those using amorphous dielectrics. VGC are structurally robust, small, and can easily be scaled to capacitance values above 100 pF.
IEEE Transactions on Applied Superconductivity


high-Q superconducting resonator, loss tangent, low-loss capacitor, low-loss resonator, superconducting qubit, vacuum-gap capacitor, vacuum microelectronics


Cicak, K. , Allman, M. , Strong, J. , Osborn, K. and Simmonds, R. (2009), Vacuum-Gap Capacitors for Low-Loss Superconducting Resonant Circuits, IEEE Transactions on Applied Superconductivity, [online], (Accessed April 24, 2024)
Created June 16, 2009, Updated February 19, 2017