Miniaturization of microwave planar higher-order filter

In this paper, a novel microwave higher-order filter design is presented using dual-mode resonators. The filter is realized in multilayer technology in order to reduce the footprint area. The structure consists of two dielectric layers separated by a common ground plane. The filter is realized with two resonators which are printed on different sides of dielectric layers. The conductive coupling between the resonators is realized with a via. The coupling between the resonators is investigated as a function of the via position. The proposed filter design achieves a size reduction of 50% as compared to classical microstrip design.