HTS narrow band filters at UHF band for radio astronomy applications

• Published in: IEEE transactions on applied superconductivity Vol. 15; no. 2; pp. 1004 - 1007
• Main Authors: Jiafeng Zhou, Lancaster, M.J., Frederick Huang, Roddis, N., Glynn, D.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY IEEE 01.06.2005; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Astronomy; Band pass filters; Capacitors. Resistors. Filters; Circuit properties; Cut-off; Electric, optical and optoelectronic circuits; Electrical engineering. Electrical power engineering; Electronic circuits; Electronics; Exact sciences and technology; Extraterrestrial measurements; Frequency filters; Harmonics; High temperature superconductors; Microwave circuits, microwave integrated circuits, microwave transmission lines, submillimeter wave circuits; microwave filters; Narrowband; Noise levels; Observatories; Performance loss; Power harmonic filters; Pulsars; Radio astronomy; Resonator filters; Ripples; Superconducting filters; Superconductivity; Various equipment and components; Harmonic; High performance; Return loss; Resonator filters; Microwave; high-temperature superconductors; Superconductor device; Microwave filter; Narrow band; Radio astronomy; UHF wave; Elliptic filter; Insertion loss; Band pass filter; microwave filters; Superconducting filters; Passband; Astronomy; High temperature superconductor
• DOI: 10.1109/TASC.2005.850170
• ISSN: 1051-8223

High performance narrow-band High-Temperature Superconductor (HTS) filters at 610 MHz with very sharp cut-off response and low loss are needed for improving the observation of pulsars at the Jodrell Bank Observatory, UK. An eight-pole quasi-elliptic HTS filter using compact resonators has been designed for this purpose. The measured response of filter has an insertion loss of 0.3 dB (including a 0.2 dB ripple), and a return loss of 15 dB in the passband. Two transmission zeroes are realized to improve the steepness of the cut-off. The lowest harmonic is designed to appear at 1.79 GHz, about three times the center frequency. The out-of-band rejection is better than 85 dB up to this harmonic. The filter has been tested in the observatory with excellent results.