Study of Flexible Printed Transmission Lines Realized by Direct-Write Printing Technology

In this paper, a fully additive approach for microwave transmission lines realization is presented. Designed transmission lines are printed with a direct-write digital printing system on a flexible polyimide substrate. Also, copper transmission lines based on conventional photolithography are prepared. Scattering parameters of the transmission lines with different dimensions are measured and reported. Also, challenges in SMA port assembling are examined. Different connection methods for measuring scattering parameters are used based on the physically assembled SMA ports and with direct measuring by Z infinity probes. For Z probes assembly, two different ground connection methods are examined: copper ribbons and vias. Reported parameters are compared to simulations. The study proves that the fully additive digital printing method is an acceptable approach to realize transmission lines.