Radiation efficiency assessment of bundled carbon nanotube antenna at terahertz frequency range

The radiation efficiency of bundled carbon nanotubes (BCNTs) for the fabrication of antennas in the terahertz frequency range is evaluated. The performance is compared against thin gold film, which is conventionally used for antenna fabrication. The macroscopic behavior of BCNTs is modeled by an anisotropic thin resistive sheet model and its surface resistivity is extracted from the theoretical distributed circuit model of a single wall carbon nanotube (SWNT). Also, a thin gold layer in terahertz band is characterized by the Drude-Smith model which calculates the theoretical conductivity of fabricated thin gold in optical frequency. Conventional half-wave strip antennas are designed to resonate from 1 THz to 50 THz and the method of moments (MoM) and the mixed potential integral equation (MPIE) techniques are utilized to calculate radiation efficiencies of the resonant strip antennas composed of BCNTs and thin gold film. The numerical simulation result shows that the radiation efficiency of a BCNT antenna is consistently lower than the efficiency of a gold film antenna in cases of BCNT equivalent density values up to 10⁴ [CNTs/μm]. However, if equivalent density values above 10⁴ [CNTs/μm] could ever be achieved, which are approximately three order of magnitude higher than the currently realizable density (10 [CNTs/μm]), BCNTs would outperform thin gold film at frequencies above 1 THz.