A direct laser-synthesized magnetic metamaterial for low-frequency wideband passive microwave absorption

Microwave absorption in radar stealth technology is faced with challenges in terms of its effectiveness in low-frequency regions. Herein, we report a new laser-based method for producing an ultrawideband metamaterial-based microwave absorber with a highly uniform sheet resistance and negative magnetic permeability at resonant frequencies, which results in a wide bandwidth in the L- to S-band. Control of the electrical sheet resistance uniformity has been achieved with less than 5% deviation at 400 & omega; sq(-1) and 6% deviation at 120 & omega; sq(-1), resulting in a microwave absorption coefficient between 97.2% and 97.7% within a 1.56-18.3 GHz bandwidth for incident angles of 0 & DEG;-40 & DEG;, and there is no need for providing energy or an electrical power source during the operation. Porous N- and S-doped turbostratic graphene 2D patterns with embedded magnetic nanoparticles were produced simultaneously on a polyethylene terephthalate substrate via laser direct writing. The proposed low-frequency, wideband, wide-incident-angle, and high-electromagnetic-absorption microwave absorber can potentially be used in aviation, electromagnetic interference (EMI) suppression, and 5G applications.

Automated summary

We report a new laser-based method for producing ultrawideband metamaterial-based microwave absorbers with uniform sheet resistance and negative magnetic permeability, resulting in a wide bandwidth. The absorbers show high microwave absorption coefficient within a certain frequency range, and can be used in aviation, EMI suppression, and 5G applications.