Ka-Band Monolithic Stereolithography 3-D Printed Broadband Passive Waveguide Devices

This paper presents a monolithic integration of two Ka-band broadband passive waveguide devices, i.e., a magic-T and an E-plane 3-dB directional coupler, that are manufactured using a stereolithography (SLA)-based 3-D printing technique. Each of them is prototyped as a whole structure instead of multiple parts. Its surface metallization is carried out by employing electroless nickel/copper plating. These devices have little redundant structural material, and exhibit light weight and good mechanical strength as well as thermal handling capability due to the use of low-density ceramic-filled resin. The magic-T demonstrates at 30-40 GHz port return losses (RLs) mostly greater than 15 dB, isolations over 17 dB, and good amplitude and phase imbalances for transmission scenarios. At 30-38 GHz, the E-plane 3-dB directional coupler exhibits port RLs over 15 dB, an isolation mostly over 25 dB, and amplitude and phase imbalances of -1-0.62 dB and (-1.5-4.5)degrees, respectively.