Josephson parametric amplifier with third-order resonator impedance matching

We propose and realize a multi-resonator coupled impedance-matched Josephson parametric amplifier. Parallel plate capacitors serve as couplers to achieve coupling between the nonlinear resonator containing the Josephson loop and the half-wavelength resonator, and between the half-wavelength resonators themselves. By precisely designing each coupling strength, we effectively extend the amplifier's bandwidth. Through a combination of circuit-level and electromagnetic field simulations, we optimize the structural parameters of the resonators and capacitors. The two measured devices have 15 dB gain with a bandwidth of 1.3 GHz and 20 dB gain with a bandwidth of 1.1 GHz, respectively, with near-quantum-limited noise temperatures.