Niobium Tunable Microwave Filter
Journal article, 2009

A superconductor bandpass filter with tunable central frequency in the range of 2.1–3.5 GHz has been implemented using Superconducting Quantum Interference Devices (SQUID). The filter is designed as two pi–network resonators connected by a transmission line. Both resonators have a SQUID inductor with a tuning range of 65–200 pH, controlled by DC current magnetically coupled to the SQUIDs. Over a frequency tunability of 40% from 3.5 to 2.1 GHz, the filter has a corresponding fractional bandwidth of 35% to 27% and a mid-band insertion loss of 0.5–3.0 dB. Due to the presence of active elements, the tunability of the filter depends on the power of the microwave signal. A maximum power of -52dBm corresponds to a frequency tuning range of 15%. Spectral measurements by controlling the central frequency of the filter with variable pulse-width shows that the filter can be tuned at a rate of 120 GHz per us.

Low Temperature Superconductor (LTS)

Superconducting Quantum Interference Device (SQUID)

high speed tuning

Niobium (Nb)

tunable filter

tunable inductance

qubit operation.


Raihan Rafique

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

Thomas Ohki

BBN Technologies

Peter Linner

Chalmers, Microtechnology and Nanoscience (MC2), Microwave Electronics

Anna Yurievna Herr

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

IEEE Transactions on Microwave Theory and Techniques

0018-9480 (ISSN)

Vol. 57 5 1173-1179 4814652

Subject Categories

Other Engineering and Technologies

Other Electrical Engineering, Electronic Engineering, Information Engineering



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