2023

Li, Hang Xi; Shiri, Daryoush; Kosen, Sandoko; Rommel, Marcus; Chayanun, Lert; Nylander, Andreas; Rehammar, Robert; Tancredi, Giovanna; Caputo, Marco; Grigoras, Kestutis; Gronberg, Leif; Govenius, Joonas; Bylander, Jonas

<p>In superconducting quantum processors, the predictability of device parameters is of increasing importance as many labs scale up their systems to larger sizes in a 3D-integrated architecture. In particular, the properties of superconducting resonators must be controlled well to ensure high-fidelity multiplexed readout of qubits. Here we present a method, based on conformal mapping techniques, to predict a resonator&amp;#x0027;s parameters directly from its 2D cross-section, without computationally heavy and time-consuming 3D simulation. We demonstrate the method&amp;#x0027;s validity by comparing the calculated resonator frequency and coupling quality factor with those obtained through 3D finite-element-method simulation and by measurement of 15 resonators in a flip-chip-integrated architecture. We achieve a discrepancy of less than 2% between designed and measured frequencies, for 6-GHz resonators. We also propose a design method that reduces the sensitivity of the resonant frequency to variations in the inter-chip spacing.</p>