Niobium Tunable Microwave Filter

作者：Rafique Raihan^*; Ohki Thomas; Linner Peter; Herr Anna Yurievna

来源：IEEE Transactions on Microwave Theory and Techniques, 2009, 57(5): 1173-1179.

DOI：10.1109/TMTT.2009.2017347

• High-speed tuning
• low-temperature superconductor (LTS)
• tunable filter
• tunable inductance

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/mu s.

• 出版日期2009-5