Stacked Feedline and Resonator Topology for Spin Qubit Control

The patent applies dimensionality change by moving the feedline and resonator from a two-dimensional coplanar arrangement to a three-dimensional stacked configuration. The feedline is placed in a first plane and the resonator in a second plane separated by a dielectric layer, enabling capacitive coupling through vertical stacking rather than horizontal parallel arrangement. This reduces the required overlap length from several hundreds of micrometers to just tens of micrometers while maintaining sufficient coupling strength, thereby significantly reducing the overall footprint of the quantum computing system.

The patent resolves this contradiction by transitioning from horizontal separation to vertical separation through stacking. The feedline and resonator are positioned in adjacent planes with a dielectric layer between them, allowing the separation distance to be precisely controlled at the thickness of the dielectric layer (typically tens of nanometers to micrometers). This vertical arrangement maintains strong capacitive coupling for high readout sensitivity while enabling standardized manufacturing processes for the dielectric layer thickness.

The patent applies multi-functionality by designing the resonator structure to serve dual purposes: it acts as both the readout resonator for measuring qubit states and as an electron spin resonance (ESR) antenna for controlling qubit operations. This is achieved by configuring the resonator with appropriate geometric parameters and coupling mechanisms that enable it to respond to both readout signals and control microwave pulses. Consequently, a single RF line can carry both control and readout signals, significantly reducing the wiring fanout and device complexity while maintaining signal integrity through proper impedance matching and frequency separation.