Inline realization of cascaded trisection and cascaded quadruplet in coaxial cavity filters

This paper proposes novel true inline configuration for realizing cascaded trisection (CT) and cascaded quadruplet (CQ) in coaxial cavity filters. Cross couplings between non-adjacent resonators are realized by changing the orientation of selected resonators, thus avoiding structural complexity required by conventional techniques. Sequential couplings between adjacent resonators are effectively controlled by shifting locations of the capacitive gaps, which allows virtually independent control of sequential and cross couplings. Full electromagnetic (EM) simulation results of filters with CT and CQ sections are used to demonstrate feasibility and compactness of the proposed filter configuration.