Novel method to improve power handling capability for coplanar waveguide high-temperature superconducting filter

This paper proposes a novel method to improve the power handling capability of a coplanar waveguide (CPW) high-temperature superconducting (HTS) filter. The noteworthy point of the proposed method is that it is based on the concept that the power handling capability is improved by reducing the maximum current density of the filter. Numerical investigations confirm that a CPW HTS filter using 66-Ω characteristic impedance resonators (66-Ω CPW HTSF) reduces the maximum current density compared to that using conventional 50-Ω resonators (50-Ω CPW HTSF). We fabricated 5-GHz band four-pole Chevyshev CPW HTSFs based on the proposed and conventional methods. The fabricated 66-Ω CPW HTSF exhibited the third-order intercept point (TOI) of + 61 dBm while the 50-Ω CPW HTSF exhibited the TOI of + 54 dBm, both at 60 K. These results indicate the effectiveness of the proposed method.