Additive Manufacturing of Complex Millimeter-Wave Waveguides Structures Using Digital Light Processing

Additive manufacturing technology has enabled the manufacturing of complex structures, especially those with intricate internal features. This paper proposes a method for building complex-structured millimeter-wave waveguides using a strategy that combines digital light processing 3-D printing technology, a curved corner design, an off-axis print angle of 45°, and a robust postmetallization process. To demonstrate the capability of this combined-strategy method, a traditional magic tee prototype and an adapted inherently matched magic tee prototype are fabricated for use in the W-band. The measured performance of the fabricated inherently matched magic tee demonstrates return loss better than 13.5 dB, isolation coefficients higher than 15.7 dB, insertion losses smaller than 1.3 dB, and a magnitude imbalance of less than 1.3 dB across 80-105 GHz. The 3-D printed magic tee has a comparable performance to a W-band CNC-machined magic tee but weighs 77.5% less than the metallic one.