Optimizing electromagnetic wave absorption performance: Design from microscopic bamboo carbon nanotubes to macroscopic patterns

Achieving ideal electromagnetic wave absorbing materials and effective artificial super structures design are increasingly attractive for their irreplaceable role in aerospace stealth structure, Over the Air (OTA) test and civil wireless communication systems. In this work, the bamboo carbon nanotubes (CNTs) were prepared by a simple thermal treatment method. The microstructure and yields of bamboo CNTs were tunable by changing the feeding amounts of polypropylene fabrics precursors. The optimal reflection losses (RL) value of as-prepared bamboo CNTs was up to -54.5 dB at 14.45 GHz with 1.85 mm, meanwhile the effective bandwidth (f(e)) covered from 12.31 to 17.76 GHz. With subsequent macroscopic honeycomb architecture design based on the as-fabricated bamboo CNTs, the artificial structures with variable radius, thickness and height exhibited more than 90% absorption in 8.5-18 GHz. The results suggested that combination of developing microscopic microwave absorbers and macroscopic structure design would fundamentally optimize the electromagnetic wave absorption with low matching thickness and extensive effective bandwidth. (C) 2019 Elsevier B.V. All rights reserved.