A High-Isolation Eight-Way Power Combiner

Abstract

A high-isolation eight-way power combiner is proposed in this article that is constructed by cascading three stages of power combiners in series. Its high isolation and low return loss are realized by means of lumped isolators, an isolated side network, and a resistive septum. The eight-way power combiner is basically a 17-port mode network, consisting of eight input ports, eight matching ports, and one output port. The mode network matrix cascade computation clearly reveals the working mechanism. Based on the designed 17-port network, an eight-way power combiner is realized with eight matching ports connected to loads. The measurements agree well with the simulations. From 7.8 to 10.2 GHz, the return loss at the input ports is greater than 19 dB, the return loss at the output port is greater than 18 dB, the isolation is at least 19 dB, and the insertion loss is less than 0.4 dB. The proposed eight-way power combiner has the merits of high isolation, low return loss, low insertion loss, high power capacity, and ease of integration, with great potential for integration into high-power amplifiers.