Investigation of Insertion Loss in Inkjet-Printed Coplanar Waveguide Based on Drying Temperature

In this study, we propose an optimized inkjet printing process to improve the insertion loss of inkjet-printed coplanar waveguide (CPW) transmission lines. The process involves varying the drying temperature and adjusting the number of printing steps to investigate their effects on the electrical characteristics of the printed CPW. The relationships between surface roughness, surface cavities, morphological changes, and insertion loss are studied by conducting atomic force microscopy analysis and by examining the insertion loss up to 3 GHz. The printed CPW that underwent low-temperature drying after the first printing and high-temperature drying after the second printing before sintering showed improved results in terms of insertion loss, surface microcavities, and surface morphology compared to the CPWs prepared under different drying conditions. In particular, the proposed process led to an improvement in the insertion loss from 0.167 dB to 0.082 dB at 3 GHz. These findings provide valuable insights for improving the reliability and efficiency of printed electronics used in high-frequency applications.