| Abstract: | The conductivity, current distribution, and radiation efficiency for a variety of dipole antennas constructed from carbon nanotube thread/rope are simulated using Hallén's integral equation for a thin wire applied to the method of moments and are compared to a standard copper wire dipole antenna. Next, the conductivity and weight of fully fabricated carbon nanotube thread and rope samples are measured and analyzed. Finally, half-wavelength copper and carbon nanotube (CNT) thread dipole antenna prototypes are fabricated, measured, and analyzed. Simulation results indicate that the CNT thread/rope antenna performance improves with increased diameter and that the application of these materials as a half wavelength dipole antenna yields manageable losses of less than 1-5 dB at RF frequencies above 10 GHz. Measured sample results demonstrate that the existing single-ply CNT thread exhibits a conductivity approximately 2-3 orders of magnitude lower than copper. The braiding method employed to produce large diameter CNT rope was demonstrated to be a poor method for increasing thread diameter and conductivity due to the additional resistive losses that the braiding geometry introduced. Dimethyl sulfoxide densification was found to be a valuable method for improving CNT thread conductivity and lowering the thread contact resistance. Dipole antenna prototype measurements confirm the functionality of the CNT thread as an antenna, albeit with a 4% downward frequency shift due to reactance effects and material losses of greater than 12 dB at 2.45 GHz as predicted by the results from the method of moments simulations. |
| Keywords: | carbon nanotubes, current distribution, dipole antennas, integral equations, method of moments, wire antennas, CNT thread conductivity, Hallé, n integral equation, braiding geometry method, carbon nanotube thread dipole antennas, dimethyl sulfoxide densification, dipole antenna conductivity, electromagnetic measurement, electromagnetic simulation, half-wavelength copper, method of moment simulations, radiation efficiency, resistive losses, rope antenna performance, rope samples, standard copper wire dipole antenna, thin wire, Antenna measurements, Conductivity, Copper, Wires, Yarn, Carbon nanotube (CNT), Hallen’, s integral equation, dimethyl sufoxide, dipole antenna |
