Broadband RF Design with MEEP: A Set of 3D-Printed Open-Source RF Horns in the multi-GHz Bandwidth

Radio-frequency (RF) antenna design and fabrication traditionally proceeds in three phases. First, the design performance is modeled with expensive, proprietary software. Second, the design is built using precision metal machining or printed circuit board (PCB) fabrication. Third, the result is characterized using RF measurement tools. The process can include machine learning for optimization. We have developed an open-source alternative process that utilizes the MIT Electromagnetic Equation Propagator (MEEP) package for design and simulation, and open-source 3D printing with conductive polymer for fabrication. Using this process, we created a set of broadband RF horn antennas. The radiation patterns and the VSWR match our MEEP calculations, while the cross-polarization ratio matches theoretical expectations. These results indicate that our creations are linearly polarized, broadband RF horn antennas with bandwidth [4.0-18.0] GHz, or a fractional bandwidth of 127%. Because the maximum frequency of our network analyzer is 18 GHz, these results are lower limits. Our results therefore represent a successful broadband open-source CEM/CAD workflow utilizing direct, repeatable conductive printing that circumvents the need for electroplating processes.