A Connectorized X-Band 3-D Printed Air-Filled Self-Suspended Rectangular Coaxial Transmission Line

This paper reports on a simplified and cost-efficient approach for realization of air-filled self-suspended rectangular coaxial transmission lines (TLs) by means of polymer-based additive manufacturing. An X-band TL prototype is devised with a wideband filter design approach. The input and output of the TL are connectorized to interface with external circuits. Architectural highlights involving the impedance matching, the assembly of RF connectors, and the sidewall openings will be discussed. The TL is monolithically prototyped by incorporating stereolithography apparatus and copper electroplating techniques, featuring low cost, easy assembly, and free of any fastening element. The implemented TL demonstrates in 8-12.4 GHz an insertion loss of 0.4-1.1 dB (an attenuation factor of 0.06-0.26 dB/cm after the connector loss is deembedded) and a group delay of 0.23-0.32 ns with a fluctuation of around 50 ps.