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 S11 ≤ −10 dB), high average radiation efficiency (76%) and fractional bandwidth (121%) with small size of 30 × 30 mm2. 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.