Microwave characterization of conducting polymer PEDOT: PSS film using a microstrip line for humidity sensor application

In this paper, we characterize the thin conducting polymer film, PEDOT: PSS, using a microstrip line in a humid environment at microwave frequencies. To characterize the thin film alone over the microstrip line, a de-embedding technique of thru-reflect-line (TRL) calibration is utilized. After the de-embedding procedure, the thin film is modeled with a transmission line, and the film’s R, L, G, and C parameters are extracted from measured S-parameters. In addition, the characteristics of the thin film has been tested in terms of electrical conductivity with increasing relative humidity (RH). In the future, it is expected that this work can contribute to the improvement of stability as well as performance of conducting polymer-based electronic sensing devices.