A Novel Microwave High-Temperature Superconducting Reaction-Type Transmitting Filter for Mobile Base Stations

A novel split open-ring reaction-type construction technique to achieve high power-handling capability for High-temperature superconducting (HTS) filters is presented. The purpose of this filter is to suppress the adjacent noise generated by transmitting power amplifiers for mobile base stations. First, it is explained that reaction-type filters are suitable for high power transmission. Secondly, novel split open-ring resonators, which reduce the maximum current density while maintaining high Q-factors are proposed. Current density dispersion effects are evaluated under the same coupling coefficient. Finally, a 5 GHz three-pole reaction-type filter using split open-ring resonators is designed. The frequency characteristics of the filter are investigated by using the method of moments. The results predict that the filter realizes both a higher power-handling capability than that of transmission-type filters and a better skirt property than existing HTS filters using dual-mode resonators.