We establish a theoretical bimodal model for the complex permeability of flaky soft magnetic composite materials to explain the variability of their initial permeability.The new model is motivated by finding the two n...We establish a theoretical bimodal model for the complex permeability of flaky soft magnetic composite materials to explain the variability of their initial permeability.The new model is motivated by finding the two natural resonance peaks to be inconsistent with the combination of the domain wall resonance and the natural resonance.In the derivation of the model,two relationships are explored:the first one is the relationship between the number of magnetic domains and the permeability,and the second one is the relationship between the natural resonance and the domain wall resonance.This reveals that the ball milling causes the number of magnetic domains to increase and the maximum initial permeability to exist after 10 h of ball milling.An experiment is conducted to demonstrate the reliability of the proposed model.The experimental results are in good agreement with the theoretical calculations.This new model is of great significance for studying the mechanism and applications of the resonance loss for soft magnetic composite materials in high frequency fields.展开更多
Microwave absorbers(MAs)with broadband and strong microwave absorption capacities are urgently required to meet the demands of complex electromagnetic(EM)environments.Herein,a novel labyrinth multiresonant metastructu...Microwave absorbers(MAs)with broadband and strong microwave absorption capacities are urgently required to meet the demands of complex electromagnetic(EM)environments.Herein,a novel labyrinth multiresonant metastructure composed of a polyether-ether-ketone/flaky carbonyl iron(PEEK/CIP)magnetic composite was proposed and fabricated via 3D printing technology.A complex multiresonant cavity design was introduced,and the resonant loss area was significantly improved.Both broadband and high-efficiency microwave absorption performances were achieved.The multilayer labyrinth multiresonant metastructure was designed with gradient impedance.The effects of structural parameters on the absorbing properties were investigated and optimized.Experiments and simulations demonstrated the effectiveness of the design strategy.The designed metastructure with a 10 mm thickness exhibited a-10 dB absorption bandwidth at a frequency of 3.78–40 GHz and an absorption bandwidth below-15 dB at 7.5–36.5 GHz.Moreover,an excellent wide-angle absorption performance was observed for different polarization states,including transverse electric(TE)and transverse magnetic(TM)modes.The combination of a complex multiresonant metastructure design and 3D printing fabrication provides a facile route to considerably extend the absorption bandwidth and strength of electromagnetic absorbers.This work is expected to provide a promising strategy for further enhancing microwave absorption performance,and the designed metastructure possesses great application potential in stealth and electromagnetic compatibility technologies.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11564024,51731001,and 11574122)the Fundamental Research Funds for the Central Universities,China(Grant No.lzujbky-2019-kb06).
文摘We establish a theoretical bimodal model for the complex permeability of flaky soft magnetic composite materials to explain the variability of their initial permeability.The new model is motivated by finding the two natural resonance peaks to be inconsistent with the combination of the domain wall resonance and the natural resonance.In the derivation of the model,two relationships are explored:the first one is the relationship between the number of magnetic domains and the permeability,and the second one is the relationship between the natural resonance and the domain wall resonance.This reveals that the ball milling causes the number of magnetic domains to increase and the maximum initial permeability to exist after 10 h of ball milling.An experiment is conducted to demonstrate the reliability of the proposed model.The experimental results are in good agreement with the theoretical calculations.This new model is of great significance for studying the mechanism and applications of the resonance loss for soft magnetic composite materials in high frequency fields.
基金supported by the Fundamental Research Funds for the Central Universities (Grant No.xzd012021041)the Analytical&Testing Center of Xi’an Jiaotong University for SEM analysis。
文摘Microwave absorbers(MAs)with broadband and strong microwave absorption capacities are urgently required to meet the demands of complex electromagnetic(EM)environments.Herein,a novel labyrinth multiresonant metastructure composed of a polyether-ether-ketone/flaky carbonyl iron(PEEK/CIP)magnetic composite was proposed and fabricated via 3D printing technology.A complex multiresonant cavity design was introduced,and the resonant loss area was significantly improved.Both broadband and high-efficiency microwave absorption performances were achieved.The multilayer labyrinth multiresonant metastructure was designed with gradient impedance.The effects of structural parameters on the absorbing properties were investigated and optimized.Experiments and simulations demonstrated the effectiveness of the design strategy.The designed metastructure with a 10 mm thickness exhibited a-10 dB absorption bandwidth at a frequency of 3.78–40 GHz and an absorption bandwidth below-15 dB at 7.5–36.5 GHz.Moreover,an excellent wide-angle absorption performance was observed for different polarization states,including transverse electric(TE)and transverse magnetic(TM)modes.The combination of a complex multiresonant metastructure design and 3D printing fabrication provides a facile route to considerably extend the absorption bandwidth and strength of electromagnetic absorbers.This work is expected to provide a promising strategy for further enhancing microwave absorption performance,and the designed metastructure possesses great application potential in stealth and electromagnetic compatibility technologies.
