Low-Pass Filter With Ultrawide Stopband for Quantum Computing Applications
Journal article, 2023

A new type of low-pass filter based on a leaky coaxial waveguide is presented. The filter has minimal insertion loss in the passband, while at the same time, high attenuation in the stopband is achieved. Thanks to its arrangement, the filter does not present parasitic leakage paths, so that, unlike conventional resonant filters, the stopband extends to very high frequencies. It is shown that a particular stopband attenuation can be obtained by adding or removing leaking sections. The coupling between the center coaxial structure and the leaking holes is investigated. A prototype is manufactured, and scattering parameters are measured up to 145 GHz. The prototype shows an insertion loss of less than 0.15 dB up to 10 GHz and an attenuation in excess of 60 dB above 70 GHz. The proposed filter is suitable for superconducting quantum computing applications, in which quantum bits are sensitive to radiation with energy high enough to break Cooper pairs.

quantum device and circuits

quantum computing cryogenic

infrared radiation

Dielectric losses




simulation and modeling

Filter design



Insertion loss


Robert Rehammar

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Technology

Simone Gasparinetti

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Technology

IEEE Transactions on Microwave Theory and Techniques

0018-9480 (ISSN) 15579670 (eISSN)

Vol. 71 7 3075-3080

Subject Categories

Atom and Molecular Physics and Optics

Other Physics Topics

Condensed Matter Physics



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