Design of A Balanced-to-Balanced Filtering Power Divider With High Selectivity

Based on the theoretically investigation of a square patch resonator, this article puts forward a new structure of second-order bandpass balanced-to-balanced filtering power divider. Two square patch resonators are arranged on two-layered substrate in a back-to-back manner. Due to coupling apertures, electric coupling, magnetic coupling and the direct coupling between the source and load are all obtained. Therefore, two transmission zeros are generated outside the bandpass for improving frequency selectivity. Meanwhile, the well performances of common-mode suppression and port-to-port isolation are also obtained through three pairs of ports.