Abstract
A High Temperature Superconductor filter operating in the C-band between 4200 and 5600 MHz has been developed for one of the radio astronomical receivers of the Sardinia Radio Telescope. The motivation was to attenuate an interference from a weather radar at 5640 MHz, whose power level exceeds the linear region of the first active stages of the receiver. A very sharp transition after the nominal maximum passband frequency is reached by combining a 6th order band-pass filter with a 6th order stop-band. This solution is competitive with an alternative layout based on a cascaded triplet filter. Three units of the filter have been measured with two different calibration approaches to investigate pros and cons of each, and data repeatability. The final performance figures of the filters are: ohmic losses of the order of 0.15–0.25 dB, matching better than −15 dB, and −30 dB attenuation at 5640 MHz. Finally, a more accurate model of the connection between external connector and microstrip shows a better agreement between simulations and experimental data.
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References
Bolli, P., Orlati, A., Stringhetti, L., et al.: Sardinia radio telescope: General description, technical commissioning and first light. Journal of Astronomical Instrumentation, 4 (3–4) (2015). https://doi.org/10.1142/S2251171715500087
Bolli, P., Gaudiomonte, F., Ambrosini, R., et al.: The Mobile Laboratory for Radio Frequency Interference monitoring at the Sardinia Radio Telescope. IEEE Antennas Propag. Mag. 55(5), 19–24 (2013)
Hong, J.-S. G., Lancaster, M. J.: Microstrip Filters for RF/Microwave Applications, ed. Chang, K., John Wiley and Sons, Inc. (2001)
Bolli, P., Huang, F.: Superconducting filter for radio astronomy using interdigitated, capacitively loaded spirals. Exp. Astron. 33(1), 225–236 (2012)
Bolli, P., Cresci, L., Huang, F., Mariotti, S., Panella, D.: A high temperature superconductor microwave filter working in C-band for the Sardinia Radio Telescope, Journal of Astronomical Instrumentation, 3 (1), (2014). https://doi.org/10.1142/S2251171714500032
Cameron, J.C., Kudsia, C.M., Mansour, R.R.: Microwave Filters for Communication Systems, John Wiely and Sons, Inc, (2007)
Huang, F.: Suppression of harmonics in Microstrip Filters Using a Combination of Techniques. IEEE Trans. Microw. Theory Techn. 63(10), 3453–3461 (2015)
Matthaei, G., Young, L., Jones, E.M.T.: Microwave filters, impedance-matching networks, and coupling structures, Artech House, pp. 100 and 432 (1980)
Huang, F.: Dual-band superconducting spiral filters including narrow band-stop notches. IEEE Trans. Microwave Theory and Techn. 57(5), 1188–1195 (2009)
Macchiarella, G., Tamiazzo, S.: Design techniques for dual-passband filters. IEEE Trans. Microwave Theory and Techn. 53(11), 3265–3271 (2005)
Acknowledgements
The authors wish to thank Luca Carbonaro from the INAF - Arcetri Astrophysical Observatory for providing useful suggestions on the mechanical design and Richard Prestage from the Green Bank Observatory for his valuable comments on the contents of the article. Finally, the authors are grateful to the Italian company Galvanelettronica Electroplating for putting a lot of R&D efforts in the plating process of the titanium carriers.
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Bolli, P., Cresci, L., Huang, F. et al. A high temperature superconductor notch filter for the Sardinia Radio Telescope. Exp Astron 45, 165–176 (2018). https://doi.org/10.1007/s10686-018-9578-1
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DOI: https://doi.org/10.1007/s10686-018-9578-1