Transmission lines on flexible substrates with minimized dispersion and losses

This work describes the characterization of high frequency transmission lines realized on flexible substrates. In order to investigate technology related aspects influencing the performance of the transmission lines the study includes two different technologies. The first one is a commercially available process applying a subtractive layer definition on Polyimide (PI) and Liquid Crystal Polymer (LCP) substrate. The second one is a reel to reel technology applying a semi additive layer definition on PI. The characterization was performed from DC up to 60 GHz and showed for the reel to reel process a higher performance at high frequencies which is mainly attributed to the more precise layer definition.