A stepped‐impedance‐stub loaded stepped‐impedance resonator (SISLSIR) is proposed to design a dual‐band bandpass filter. The even‐ and odd‐mode frequencies and the coupling strength of the proposed resonators can be independently designed and adjusted. A dual‐feedline structure is used to meet the required external couplings of the 2 passbands. Thus, both the center frequencies and the bandwidths of the 2 passbands can be independently controlled. A 6‐pole dual‐band filter with the passbands of 3300∼3600 MHz and 4800∼5000 MHz is successfully designed using the proposed method and fabricated with YBCO/MgO high‐temperature superconducting (HTS) wafer. The measured results of the filter exhibit high performance and match well with the simulations. The measured insertion losses are less than 0.2/0.3 dB, and the return losses are greater than 15/14 dB for the lower/upper passbands, respectively. The out‐of‐band rejection is greater than 68 dB up to 12 GHz.
A compact superconducting lowpass filter (LPF) composed of a pair of symmetrical parallel coupled lines, a cross-shaped patch and a modified E-type feeding structure is proposed. The filter is successfully designed and fabricated on MgO substrate with a compact size of 10.0 × 15.0 mm. Measured results match well with simulation results. The LPF has a 3 dB cutoff frequency of 2.18 GHz, relative stopband bandwidth of 160%, and 0.06 dB insertion loss in the passband. For attenuation level of −18.5 dB, stopband bandwidth is from 3.16 to 19.25 GHz.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.