Wideband Four-Way Filtering Power Divider With Isolation Performance Using Three Parallel-Coupled Lines

A wideband four-way power divider (PD) with filtering response and high isolation is presented. This divider is formed by connecting a pair of three parallel-coupled lines and two stepped-impedance open-circuited stubs to output ports of a traditional Wilkinson PD. In addition, three resistors, including two air-bridged resistors, are properly placed to achieve perfect isolations between all output ports. A prototype of the proposed PD is designed, simulated, and measured. The measured results validate the 86.4% bandwidth centered at 3.68 GHz with more than 15-dB out-of-band rejection, more than 17-dB isolations, and less than 0.3-dB amplitude imbalances, respectively.