Microwave drive lines

Drive your qubits!

Microwave drive lines for superconducting qubits provide signals to carry out gate operations. The key requirements on this line type are the signal integrity in the operational range (6-8 GHz) as well as their isolation and noise level.

General Specifications

Storage temperature0 K to 320 K
Operating temperature0 K to 400 K (gradient)
ApplicationsQubit drive for super-conducting qubits or similar
Number of channels8
Transmission typeStripline
Connector typeSMA female / SMP
Primary flex materialsPolyimide, Silver
Minimum bending radius5 mm
Required length for 180° longitudinal rotation10 mm
Vacuum feedthrough connection​KF25/40, ISO 100
side and top loader ports
Vacuum feedthrough leak rate< 10-9 mbar L/s

Cable overview

The product includes SMA/SMP connector blocks to interface to the room-temperature electronics and chipholder at the mK stage. They are provided with vacuum feedthroughs designed to carry multiple flexes through the vacuum barrier and are compatible with most fridge types (Bluefors, Oxford Instruments and more). The chain of attenuators (total -50 dB) is integrated into the flexible substrate and located at the thermal clamps for optimal thermalization and electron noise, with additional 8 GHz low-pass filtering located at the 0.6 K stage. Below the 100 mK plate, infrared filtering is placed and thermalized with a slope of -1dB/GHz to further filter out high frequency radiation.

Used for

Optimised for

Key Features​

Microwave Response

A microwave drive line is optimised for low loise microwave transmission up to 8 GHz. In this way one can apply microwave drive signals to your qubit or cryogenic circuit, without opening noise channels.

With 50 dB attenuation distributed over different temperature stages one obtains the optimal balance between active heat load, and opening loss channels through loss channels.

With a low-pass filter at 8 GHz and a an IR-filter on flex your circuits are maximally protected for high-frequency interference.

Cross Talk

Cross talk is what we experience daily. Whether it is picking up unwanted conversations in the train, or a phone connection suffering from interference. 

Cri/oFlex® has been designed such that each qubit is addressed individually. Learn more about cross talk in our core technology section.

How to


Cri/oFlex® into your system?

Cri/oFlex® can fit in your system in many ways and Delft Circuits has multiple approaches to find a perfect fit for your wishes, options range from a one-stop-shop in cabling solutions or a full service I/O provider designing a specific solution for your I/O challanges.

Need some help picking the right option?

First questions to ask yourself is how your system is currently wired. Do you have a port available or full loader you would like to install, upgrade or add wiring to?

For ports Delft Circuits recommends choosing from our wiring ports solution, if you want to fill a single port with more cables or get a lower heatload etc. etc. and already know exactly what cables you want pick the Wiring ports option. if you want a hassle free solution with installation, service, calibration. We recommend going for the turn-key solution and see what else we can do for you.

Delft Circuits recommends

Wiring ports

Delft Circuits recommends


For ports Delft Circuits recommends choosing from our wiring ports solution, if you want to fill a loader with more cables or get a lower heatload etc.. If you want a hassle free solution with installation etc. etc. we recommend going for the turn-key solution and see what else we can do for you

Delft Circuits recommends

Delft Circuits recommends

If you are building a new system we recommend looking at everything we have to offer for you, next to just I/O we can help you design, help you optimize, do cryogenic calculations, calibrations and much more.

Delft Circuits recommends

Dive deeper into

Cri/oFlex® technology

Learn all about what makes our technology specially fitted for the quantum industry

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