High-selectivity and miniaturized filtering wilkinson power dividers integrated with multimode resonators

This paper presents two filtering Wilkinson power dividers (FWPDs) with high selectivity and miniature size. A multimode resonator is used to replace a quarter-wavelength transmission line in a conventional Wilkinson power divider, and then the resonator-based FWPD is capable of splitting power and selecting frequency simultaneously. Two tri-mode resonators and two quad-mode resonators are applied to design a single- and a dual-band FWPD, respectively. Characteristics of the tri- and quad-mode resonators are analyzed, and the equivalent circuits of the proposed single- and dual-band FWPDs are presented. The input port matching and filtering response are explained by the even-mode equivalent circuit, while the output port matching and isolation characteristics can be investigated by the odd-mode equivalent circuit. Moreover, the magnetic source-load coupling introduces multiple transmission zeros to improve the frequency selectivity. All measured results are in good agreement with the full-wave simulation results.