Free-space reconstruction of the electrical properties of carbon nanotube based composites in the Q-band range

A free-space transmission-reflection measurement method for the non-destructive electrical characterization of carbon nanotube based composites was developed. Specifically, this versatile method measures the dielectric properties of the sample in the Q-band, corresponding to a frequency range of 30 GHz to 50 GHz, and can be used with specimens that are either thinner or thicker than the radiation penetration depth. This method also involves an error correction model in order to accurately reconstruct the constitutive dielectric properties of the composites from the measured scattering parameters. In order to perform the error-correction only two reference scattering parameters measurements are required: one from a metal plate of known reflection coefficient and the other from air with no specimen. The simplicity of our error-correction model makes the method attractive for research, development, and for quality control in the manufacturing environment.