No abstract

No abstract

This article presents a 10‐pole high‐temperature superconducting (HTS) wideband microstrip bandpass filter with a novel configuration and compact size.The filter at 10 GHz with a fractional bandwidth of 40% is designed and fabricated on a 32.6 mm × 6.7 mm × 0.5 mm MgO substrate with double‐sided YBCO films. The internal couplings between quarter‐wavelength resonators are realized by parallel‐coupled microstrip line (PCML) structure and capacitive open‐ended stubs. The strong external couplings required by wideband filter are realized by impedance steps and capacitive stubs. The measured results at 55 K, without any tuning, show a high performance. The insertion loss is less than 0.31 dB, the return loss is better than −14 dB, and the out‐of‐band rejection is higher than 70 dB. The overall measurements are in good agreement with the simulations. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1027–1029, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27485

No abstract

This article presents a four-pole continuously tunable high-temperature superconducting combline filter at L band on MgO substrate. Gallium Arsenide varactors are used as tuning elements in the filter. Additional varactors are used to tune the external quality factor of the input and output couplings. A shorted U-shape secondary coupling line is introduced to match the desired couplings so as to maintain a good return loss in the entire tuning range. The four-pole filter achieves a tuning range of 11.5% from 983.85 to 1103.6 MHz. The insertion loss is 0.46 dB at 1103.6 MHz with the bias of 9 V. The unloaded quality factor of the resonators in the four-pole filter is estimated to be 710 at 1077.6 MHz.