Superconducting Parametric Amplifier Impedance Matching With CPW Stubs

The patent extracts the traditional complex impedance matching network and replaces it with a simplified coplanar waveguide structure with optimized characteristic impedance. By removing unnecessary matching components and using direct coplanar waveguide connections with specific impedance values (e.g., 50Ω, 70.7Ω), the design achieves impedance matching without the complexity of traditional multi-component matching networks, thereby improving manufacturing yield while maintaining performance.

The patent changes the key parameter from structural complexity to electrical parameter optimization. Instead of using complex physical structures for impedance matching, the invention optimizes the characteristic impedance parameter of the coplanar waveguide (adjusting conductor width, spacing, and substrate properties) to achieve proper impedance matching. This parameter-based approach simplifies the structure and makes manufacturing more reliable.

The patent substitutes traditional dielectric capacitance (which suffers from loss) with kinetic inductance-based capacitance simulation using superconducting coplanar waveguide structures. By using the kinetic inductance of superconducting materials to simulate capacitive behavior, the design eliminates dielectric losses while maintaining the required capacitance function, thereby reducing insertion loss and improving amplifier performance.

The patent employs composite superconducting structures (combining conductors, substrates, and oxidation layers) to create lossless capacitance simulation. The composite coplanar waveguide structure uses superconducting materials with specific properties to achieve both the capacitance function and minimal loss, replacing traditional lossy dielectric capacitors with a superconducting-based equivalent.

The patent removes complex impedance matching components and networks from the design, replacing them with simplified coplanar waveguide structures. This extraction of unnecessary complexity directly reduces manufacturing cost by eliminating multiple fabrication steps, materials, and assembly operations while maintaining impedance matching performance through optimized waveguide impedance.

The patent merges the impedance matching function directly into the coplanar waveguide transmission line structure itself, rather than using separate matching networks. By combining the transmission and impedance matching functions into a single integrated structure, the design reduces component count and simplifies manufacturing, thereby lowering cost while maintaining performance.