Simulation of transient phenomena in carbon nanotubes dipoles in the far-infrared regime

Direct numerical simulation methods in the time-domain have been widely applied in electromagnetics [1]. Some advantages of direct time-domain formulations are that they reduce computational times in the study of short pulse radiation and highly-resonant structures, and provide a clear description of the electromagnetic phenomena involved [2]. The finite-difference time-domain method (FDTD), based on the direct solution of the time-domain Maxwell's curl equations, has become widely used as it can handle complex geometries and materials with arbitrary electrical properties. More recently in the field of carbon nanotube (CN) antennas, FDTD has been employed in the analysis of both SNWT [3] as well as arrays of CN dipoles [4]. However, even in relatively simple cases such as arbitrarily oriented thin-wires it has limited accuracy and high computational costs. In contrast, the time-domain electric-field integral equation (TD-EFIE) solution using the method of moments in the time domain (MoM-TD) is well suited for the study of thin wires embedded in a homogeneous environment and has considerably lower computational costs compared with FDTD. In this paper, the TD-EFIE is utilized for accurately and efficiently simulating the electromagnetic properties of CN antennas. Results presented here demonstrate the advantages of using a formulation based on the TD-EFIE. The physical insight provided by the method is also briefly discussed.