Improving Power-Handling Capability of 4-Pole HTS Filters by Expanding Line Width of Resonator 2 With Narrow Slits

We propose the use of a 4-pole high temperature superconducting (HTS) transmitting filter in which the line width of resonator 2 has been expanded with narrow slits. We designed a Chebyshev BPF using the Sonnet EM software and calculated the current density distribution of each resonator. The power-handling capability of the HTS filter with narrow slits (number of slits: 14, Gap: 0.04 mm) was expected to improve by approximately 4.0 dB from an electromagnetic simulation. To clarify the effect of the narrow slits, we fabricated an HTS filter in which only the line width of resonator 2 was expanded and one using the narrow slits, and measured the frequency response and power handling capability. The fabricated filters showed band-pass characteristics, and the power-handling capabilities were up to 9.8 dB compared with the case where only the line width of resonator 2 was expanded.