High-frequency characteristics of conducting polymer for gas-sensor

In this paper, we report the intrinsic characteristics of conducting polymer for gas-sensor at high frequency region, i.e., 500 MHz to 10 GHz. To investigate the high-frequency characteristics of conducting polymer (CP), a coplanar waveguide electrode (CPW) is utilized. First, a CPW without CP, i.e., an open CPW, is simulated by a full-wave electromagnetic solver. From the simulated and measured result, we find that the open CPW shows clearly capacitive component. For a CPW with CP, it shows constant transmission characteristic of approximately 3-4 dB level at overall frequency region. This indicates that CP may be a good sensing material for detection of various gases or vapors in the high frequency region because its electrical properties can be sensitively varied with surface modification of gas absorption and desorption. As a result, if CP is possible to realize the various radio-frequency (RF) circuits and devices, we suggest that it can be used for diverse RF gas- as well as bio-sensing applications.