Design and Characterization of an All-Metal 3-D Printed Air-Dielectric Coaxial Line

The design and fabrication of a low-cost, wideband fully 3-D-printed coaxial line with air-dielectric is demonstrated. Support of the inner conductor is achieved with shorted stubs, the shape and length of which are determined with electrical performance and manufacturing requirements in mind. Direct metal laser sintering (DMLS) fabrication is leveraged for manufacturing, enabling fully monolithic fabrication and follow-up integration with 2.4-mm connectors. Measurements show a return loss of >20 dB and an insertion loss of <0.35 dB for 12-mm-long line from 20 to 39 GHz. Agreement with full-wave simulations indicates that there is a great practical potential for DMLS components and systems based on coaxial lines at these frequencies.