Designing Electronic Structures of Multiscale Helical Converters for Tailored Ultrabroad Electromagnetic Absorption

Area of Science:

• Materials Science
• Nanotechnology
• Electromagnetics

Background:

• Tailoring electronic structure and physicochemical properties of electromagnetic wave absorption (EMWA) materials is crucial.
• The precise relationship between material configuration and electromagnetic (EM) loss mechanisms remains poorly understood.

Purpose of the Study:

• To synthesize novel in situ Mn/N co-doped helical carbon nanotubes for ultrabroad EMWA capability.
• To elucidate the EM loss mechanisms in these engineered nanomaterials.

Main Methods:

• Synthesis of in situ Mn/N co-doped helical carbon nanotubes inspired by DNA transcription.
• Theoretical calculations and EM simulations to analyze electronic structure and EM loss.
• Fabrication of macroscale gradient metamaterials for broadband EMWA.

Main Results:

• Mn/N co-doped helical carbon nanotubes exhibit enhanced EM loss due to Mn-N4-C orbital coupling, spin polarization, and helical structure cross-polarization.
• HMC-8 achieved a minimum reflection loss of -63.13 dB at 1.29 mm thickness.
• HMC-7 demonstrated an effective absorption bandwidth (EAB) of 6.08 GHz at 2.02 mm thickness.
• Gradient metamaterials achieved an ultrabroadband EAB of 12.16 GHz at 5.00 mm thickness, with a maximum radar cross section reduction of 36.4 dB m^2.

Conclusions:

• The study establishes a link between metal-nonmetal co-doping configurations and EM loss mechanisms.
• The developed helical carbon nanotube converters provide a promising platform for high-performance EMWA.
• This work contributes to advancing the understanding and application of broadband EMWA materials.