3D-Printed Broadband Power Divider based on Helical-Microstrip Transmission Line Segments

This paper presents the design and electromagnetic characterization of a 3D-printed 2-way broadband power divider intended to work in the RF band from several hundred MHz up to a few GHz. The design of the power divider is based on the use of helical-microstrip transmission line segments. Two different topologies of tapered helical-microstrip segments are considered prior to deciding on the final design of the power divider. The characteristic impedance profiles of both topologies are analyzed by means of electromagnetic simulation using the finite element method. After checking the performance of the segments in comparison with an ideal exponential profile, we propose an optimized design for the tapered impedance transformer. Two such optimized transformers are connected to configure the power divider as a compact 3-port device. We then fabricate and test a demonstrator prototype of this proposed broadband power divider design. Our experimental results show a good agreement with the performance predicted by electromagnetic simulations. These results demonstrate the potential of helical-microstrip technology to reduce the length of the transmission line segments required to implement such a power divider. A compaction factor of 4-5 was achieved, compared to an ideal design operating in the same frequency range.