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- Rafique, Raihan, 1978, et al.
(författare)
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Miniaturization of superconducting passive filters for on-chip applications
- 2007
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Ingår i: 11th International Superconducting Electronics Conference, Washington DC, USA, June 10-14, 2007.. ; 11, s. P-V09
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- We present techniques to miniaturize superconducting ultra narrowband filters for on-chip applications. The filters are designed for 2 GHz, 5 GHz and 10 GHz operating frequencies. The expected bandwidths of the designed filters are 2-20 MHz. The designs are of 7 stages Chebyshev filters having maximum passband ripples of 0.5 dB. On-chip filters are particularly interesting as they are applicable for monolithic design with the RSFQ circuit aiming qubit applications. One of the designs is a quasi-lumped filter where the effective wave propagation constant has been increased by the addition of lumped components to the superconducting microstrip line (SMSL). Additionally, this design provides the optimum width of an SMSL without violating design rules. The other design consists of distributed and lumped components. The area of the filter is in the range of 1-2 square mm. We present the filter topologies and corresponding experimental results for the frequency response of these on-chip filters designed for Hypres 4.5 kA/cm2 fabrication process.
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| 2. |
- Rafique, Raihan, 1978, et al.
(författare)
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Miniaturized superconducting microwave filters
- 2008
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Ingår i: Superconducting Science and technology, press.
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we present methods for miniaturization of superconducting filters. We consider two designs of 7th order bandpass Chebyshev filters based on lumped elements and a novel quasi-lumped element resonators. In both designs the area of the filters, with a central frequency of 2-5 GHz, is less than 1.2 mm2. Such small filters can be readily integrated on one board for multi-channel microwave control of superconducting qubits. The filters have been experimentally tested and the results are compared with simulations. The miniaturization resulted in parasitic coupling between resonators and within eachresonator that affected primarily stopband and bandwidth increase. The severity of the error depends on the design in particular, and was less prawn when groundplane was used under the inductances of the resonators. The best performance was reached for the quasi-lumped filter with central frequency of 4.5 GHz, quality factor of 100 and 28 dB stopband.
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| 3. |
- Rafique, Raihan, 1978, et al.
(författare)
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Niobium Tunable Microwave Filter
- 2009
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Ingår i: IEEE Transactions on Microwave Theory and Techniques. - 0018-9480 .- 1557-9670. ; 57:5, s. 1173-1179
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Tidskriftsartikel (refereegranskat)abstract
- A superconductor bandpass filter with tunable centralfrequency in the range of 2.1–3.5 GHz has been implementedusing 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.
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| 4. |
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| 5. |
- Rafique, Raihan, 1978, et al.
(författare)
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Tunable Impedance Matching Network
- 2008
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Ingår i: GigaHertz Symposium, March, 2008. ; , s. 15-
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Konferensbidrag (refereegranskat)abstract
- We present superconducting SQUID based tunableimpedance matching networks designed for highly miniaturized filters. The performance of miniaturized filters is very sensitive to parasitic and fabrication related spread. The presented experimental results show that using tunable impedance matching networks, the degraded performances of these types of filters isimproved.
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