Modified Semi-Additive Manufacturing of PCBs for Enabling Accurate Device Measurements at Millimeter-Wave and Sub-Terahertz Frequencies

This paper explores the potential of the modified semi-additive process (mSAP) for precise manufacturing and measurement of structures on printed circuit boards (PCBs), with a particular emphasis on high-frequency applications. One example discussed in this paper is the measurement of a substrate-integrated waveguide (SIW) loaded with mushroom metasurface unitcells. Given the high sensitivity of metasurface structures to fabrication errors, this serves as a relevant case study. Our invetigation includes a detailed evaluation, incorporating X-ray analysis, a cross-sectional analysis, and S-parameters measurements up to 150 GHz using customized multiline thru-reflect-line (TRL) with uncertainty analysis. The measurement results show strongly agree with electromagnetic(EM) simulation, highlighting the suitability of mSAP technology for accurate fabrication and enabling measurement of high-frequency devices.