Miniaturized Inline Bandpass Filters Based on Triple-Mode Integrated Coaxial-Waveguide Resonators

This work presents a design technique to implement miniaturized cross-coupled bandpass filters in inline physical configurations based on triple-mode resonators. Triple-mode resonances are obtained by using integrated coaxial-waveguide cavity They consist of two coaxial conducting posts placed the sidewalls rectangular waveguide cavity. In proposed triplet, transmission zero (TZ) can be positioned at any sides passband simply locating either same wall or opposite walls Coaxial-to-waveguide mode coupling is implemented means screws, which adds flexibility terms tuning easiness. Three 9.9-GHz proof-of-concept prototypes corresponding third- and sixth-order designed electromagnetic-simulation level. Furthermore, triplet with TZ below manufactured characterized experimentally validate engineered 3-D RF filter principle its underlying theory.