Design of a compact hybrid filter using microstrip resonators and surface mounted cavities

A novel hybrid filter design based on low-Q microstrip resonators and high-Q surface mounted cavities is presented. The proposed structure is composed of quarter-wavelength resonators coupled with metallic cavities, which include capacitive posts for reducing the footprint. A six-pole quasi-elliptic filter is designed regarding specifications for a C-band satellite equipment. The design is detailed and initial experimental results are given.