Circuit Model Extraction of Coupled-Resonator Diplexers and Multiplexers With Unconventional Topologies

This article proposes a modular circuit model extraction framework for coupled-resonator diplexers and multiplexers with unconventional topologies. Merely, based on two-port data available in most application scenarios, the channels and especially the complicated common junction of the multiplexers can be extracted based on the proposed framework. To realize the efficient extraction of complex high-order multiport networks, the proposed method decomposes the original problem into the extraction of multiple two-port channels and a low-order multiport junction individually. First, with other channels viewed as the “black box,” each channel is extracted analytically from the measured two-port scattering parameters, where the other ports are terminated with matched loads. Afterward, the multiport scattering parameters are recovered analytically from the two-port results using the network superposition approach. From the multiport parameters, the complicated and unconventional common junction can be extracted. To validate the effectiveness of the proposed approach, this article presents the circuit model extraction examples of a fabricated diplexer and an electromagnetic (EM) simulated triplexer.