DocumentCode :
1238197
Title :
Niobium Tunable Microwave Filter
Author :
Rafique, Raihan ; Ohki, Thomas ; Linnér, Peter ; Herr, Anna Yurievna
Volume :
57
Issue :
5
fYear :
2009
fDate :
5/1/2009 12:00:00 AM
Firstpage :
1173
Lastpage :
1179
Abstract :
A superconductor bandpass filter with tunable central frequency in the range of 2-3.5 GHz has been implemented using superconducting quantum interference devices (SQUIDs). The filter is designed using 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 current magnetically coupled to the SQUIDs. Over a frequency tunability of 1.5 GHz, the filter has a mid-band insertion loss of 0.5-3.0 dB and corresponding maximum unloaded quality factor of 40. Due to the presence of active elements, tunability of the filter depends on the power of the microwave signal. A maximum power of -52 dBm corresponds to a frequency tuning range of 15%. Spectral measurements by controlling the central frequency of the filter with variable pulsewidth shows that the filter can be tuned at a rate of 120 GHz/mus.
Keywords :
Q-factor; SQUIDs; band-pass filters; niobium; radiofrequency filters; Nb; SQUID inductor; frequency 2 GHz to 3.5 GHz; frequency tuning; loss 0.5 dB to 3 dB; maximum unloaded quality factor; microwave signal power; mid-band insertion loss; niobium tunable microwave filter; pi-network resonators; spectral measurements; superconducting quantum interference devices; superconductor bandpass filter; transmission line; High-speed tuning; low-temperature superconductor (LTS); tunable filter; tunable inductance;
fLanguage :
English
Journal_Title :
Microwave Theory and Techniques, IEEE Transactions on
Publisher :
ieee
ISSN :
0018-9480
Type :
jour
DOI :
10.1109/TMTT.2009.2017347
Filename :
4814652
Link To Document :
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