Compact triple-band high-temperature superconducting filter using coupled-line stepped impedance resonator(C-SIR)

A compact triple-band high temperature superconducting (HTS) filter using coupled-line stepped-impedance-resonator (C-SIR) has been proposed in this paper. The resonant characteristics of the C-SIR are investigated by the even/odd-mode analysis. Owing to the coupled-line feed-lines structure, multiple transmission zeros are created to improve the selectivity of the filter. The resultant filter shows a competitive merit in size miniaturization. For demonstration purposes, a triple-band filter operating at 1.57GHz (GPS band), 3.5GHz (WIMAX band), and 5.5GHz (WLAN band) is designed, fabricated, and measured. Good agreement between the simulated and the measured results is observed.