High-Frequency Characterization of Printed CPW Lines on Textiles using a Custom Test Fixture

A screen printer is used to print conductive inks, loaded with silver particles, on nonwoven textiles substrates. To evaluate this technology for use as flexible interconnects; a custom test fixture was designed to assist in the high frequency characterization of CPW transmission lines. Due to the flexible nature of textile substrates it is necessary to have mechanical support at the points of electrical contact. However, the test fixture must not alter the electrical characteristics of the CPW lines. This test fixture removes the electrical effects of the mechanical support, and provides a simple and repeatable methodology for evaluating various types of textiles substrates, conductive inks, geometrical variations, and other parameters. Time-domain reflectometry (TDR) is used to measure the characteristic impedance of samples across geometrical variations in the 10 cm long CPW lines. A comparison showing the effects of the measuring the samples using the test fixture to measuring the samples on a solid acrylic substrate, and a metal plate are presented