Multilayer dual-mode filter based on substrate integrated hexagonal cavity (SIHC)

A novel multilayer dual-mode filter based on substrate integrated hexagonal cavity (SIHC) that supports two degenerated modes is demonstrated. The proposed filter is composed of a modified extended-doublet. By profit from two coupled dual-mode hexagonal cavity and asymmetry feeding structure, three transmission zeros (TZs) are generated. Accordingly, the filter not only has good selectivity due to three controllable TZs, but also has a small size by the virtue of multilayer structure. Example filter at X-band is designed and presented to demonstrate the validity of the proposed structure. Measured Results agree well with the simulated ones, with its good performance predicted.