WITHDRAWN - Quantum I/O for the KQbit Era: Integrating Cryogenic Microwave Components in a Flexible Stripline

Scalability issues in cryogenic control hardware occur due to the need for individually addressable qubits, combined with the ultra low-temperature and vacuum requirements. Conventional coaxial connectivity solutions have limited scaling potential towards and beyond the kQbit era due to cost, form factor, heat-load and unwanted resonances. In this work, we present the latest advances in the development of a monolithic, multilayer, flexible circuit, which directly connects room temperature to a milliKelvin interface of a quantum device. Specifically, we show our results of integrating microwave filtering components inside of the flexible substrate, and show a further kQbit era scaling plan through the use of the mentioned integrated filters in conjunction with superconducting striplines. We also present a combination of planar low-pass and metal powder filters in a superconducting stripline that maintains a noise-floor limited stop-band up to 50GHz. Finally, we address the thermalization of our integrated attenuators, which prevents localized thermal noise sources that are present in conventional attenuator solutions.