Full-wave analysis of coupling between combline resonators and its application to combline filters with canonical configurations

Resonant frequencies and coupling coefficient between two combline cavities, in the presence of other cavities, are obtained accurately using the mode-matching technique. The effect of iris dimensions and position on the electric and magnetic coupling is rigorously investigated. The corresponding data for two isolated cavities are included for comparison. The adjacent and nonadjacent couplings are rigorously investigated for different configurations of three coupled cavities. A four-pole slot-coupled elliptic combline filter is designed.