Direct laser-patterned ultra-wideband antennae with carbon nanotubes.

Ultra-wideband (UWB), a radio transmission technology with wide bandwidth exceeding the minimum of 500 MHz or at least 20% of the center frequency, is a revolutionary approach for short-range high-bandwidth wireless communication. In this study, carbon nanotube (CNT) UWB antennas by direct laser-patterning technology have been successfully designed, fabricated and characterized. In contrast with traditional fabrication methods, the direct laser-patterning technology offers an exceptional potential for custom-designed, high-complexity and accuracy device fabrication. The "engraving" process on CNTs exposed to laser can be attributed to the bond breaking of C-C, evaporation of carbon atoms, and oxidation of CNTs by the oxygen molecules. Numerical analysis and experimental studies provide characteristics of CNT slot antennas with a wide impedance bandwidth (from 3.4 GHz to 14 GHz for S ≤ -10 dB), high average radiation efficiency (76%) and fractional bandwidth (121%) with small size of 30 × 30 mm. The results indicate the advantages of laser-patterned UWB antennas based on carbon nanotubes, which paves the way for industrial applications, particularly in the world of consumer electronics.