Ultralight broadband microwave-absorbing materials based on the short fibers of glass-coated amorphous magnetic microwires

Abstract

Glass-coated amorphous magnetic microwires (GAWs) typically have a glass skin and amorphous metal alloy inner core, giving them special electromagnetic (EM) properties. GAWs not only exhibit multiple EM losses and suitable impedance matching but also have a conductive core with magnetic properties. In this study, GAW filament fibers (LFs) and short fibers (SFs) were prepared, and they exhibited completely different EM performance. LFs with filaments closely arrayed reflected EM waves and could thus act as an EM shielding material, whereas SFs with randomly distributed fibers demonstrated excellent microwave-absorbing (MA) properties. Single-layer SFs of just 3 g/m2 and a length of 5 mm had a minimum reflectivity (RL) of −20.4 dB at 12.3 GHz, and the effective absorption bandwidth (EAB) of RL< −10 dB was 5.36 GHz with a thickness of just 1 mm. Moreover, the MA properties of the SFs were obtained and controlled by adjusting the length, content, and lamination of the SFs in accordance with their multiple MA mechanisms. Double-layer SFs with a thickness of 2 mm could also achieve an EAB (RL< −10 dB) above 10 GHz. The novel and effective strategy proposed in this study can thus produce SFs GAWs from ultralight MA fabric that exhibit excellent MA properties and broadband.