Microwave conductance of semicontinuous metallic films from coplanar waveguide scattering parameters

Conductance of thin semicontinuous metallic films is measured in coplanar waveguide configuration at frequencies of 1 GHz to 20 GHz. The presented model of the microwave network correlates the experimental scattering parameters (S₁₁) and (S₂₁) with complex impedance and propagation constant, from which we are able to determine the films surface conductance, coefficients of reflectance, transmittance and dissipation. The measurement is illustrated on films of gold, 4 nm to 12 nm thick. After percolation from individual nanoparticles, films thicker than 10 nm resemble a continuous conductor. The presented methodology accurately captures the insulator to conductor transition, and can be used to determine microwave characteristics of such materials.