Design, Additive Manufacturing, and Characterization of a Symmetric 3-Way Wilkinson Power Divider/Combiner

Abstract

This work presents the design, manufacturing and electromagnetic characterization of compact 3-way Wilkinson power divider/combiner prototypes intended to work in the sub-GHz frequency band. The primary objective is to create practical designs in terms of size while achieving a highly symmetric electromagnetic behavior. To accomplish this, a combination of additive manufacturing techniques and copper electroplating processes was employed. Additive manufacturing enables the design of very compact 3D structures, such as helical-microstrip transmission lines, which can reduce the dimensions of the prototypes without compromising wave propagation. Additionally, its 3D nature allows for the design of completely symmetric structures, unattainable with planar technologies. The high quality of electroplated copper ensures low losses. Two prototypes, designed to operate at target center frequencies of 250 MHz and 600 MHz, respectively, were implemented. For comparison purposes a planar 3-way Wilkinson device designed to operate at a target center frequency of 600 MHz was also implemented. S-parameters were simulated and measured around the respective target frequencies to derive port impedance matching, port isolation, and insertion losses. The obtained results confirm the feasibility of very compact Wilkinson devices at the sub-GHz frequency range, with low losses and highly symmetric behavior.