Vacuum-gap-based lumped element Josephson parametric amplifier

We propose a lumped element Josephson parametric amplifier with vacuum-gap-based capacitor. The capacitor is made of quasi-floating aluminum pad and on-chip ground. We take a fabrication process compatible with air-bridge technology, which makes our design adaptable for future on-chip integrated quantum computing system. Further engineering the input impedance, we obtain a gain above 20 dB over 162-MHz bandwidth, along with a quasi quantum-limit noise performance. This work should facilitate the development of quantum information processing and integrated superconducting circuit design.