Frequency-Independent Circuit Model for One-Dimensional Carbon Nanostructures

We demonstrate that a frequency-independent parallel RC circuit is the simplest model that accurately describes high-frequency electrical conduction in 1-D nanostructures. The resistance is determined from dc measurement, and the capacitance is extracted directly from the measured S-parameters for a ground-signal-ground test structure, without using any fitting parameter. The methodology is applied to carbon nanofibers, and the RC model yields results that are within ??0.5 dB and ??5?? of the measured S-parameters up to 50 GHz. The model is further justified by examining the relationship between S- and Y-parameters of the test network.