Nondestructive Complex Permittivity Measurement of Conducting Materials Using Open-ended Coaxial Probes

In regard to their physical properties, intrinsically conducting polymers are very good candidates for electronic applications. In this paper, we present the open-ended coaxial method to measure the complex permittivities of Polyaniline/Polyurethane conducting composites at nearly percolation threshold in microwave band. At the microwave frequencies, the permittivities follow the power law (epsiv proportional to f^-s) in agreement with the hopping theory. For blends with 1% of Pani, the loss factor (tan delta) had interesting value (tan delta = 3.2 at 1GHz) for use as microwave absorbing materials.