Considerable microwave absorption performance at elevated temperatures is highly demanded in both civil and military fields.Single dielectric or magnetic absorbers are difficult to attain efficient and broadband micro...Considerable microwave absorption performance at elevated temperatures is highly demanded in both civil and military fields.Single dielectric or magnetic absorbers are difficult to attain efficient and broadband microwave absorption at the high temperature range of 373 K-573 K,and the evolution mechanism of the microwave absorption is still unclear especially for the magnetic absorbers.Herein,ZnO coated flaky-FeCo composite is proposed to break through the bottleneck,which possesses microwave absorption(RL<-10 dB)that covering the whole X band(8.2 GHz-12.4 GHz)at the temperature range of 298 K-573 K with a thickness of only~2 mm.Moreover,attenuation mechanism and evolution of the microwave absorption properties for the FeCo@ZnO flaky material at elevated temperature has been clearly disclosed by the composition and microstructure characterizations,electromagnetic performance measurements and first principles calculations for the first time.Moreover,the Poynting vector,volume loss density,magnetic field(H)and electric field(E)are simulated by HFSS to understand the interaction between EM waves and the samples at different temperatures,further elaborating the attenuation mechanism in high-temperature environment.This study provides guidance in designing and developing high-temperature microwave absorbers for the next generation.展开更多
Genetic algorithm(GA)is utilized to design microstrip patch antenna shapes for broad bandwidth.A new project based on GA and high frequency simulation software(HFSS)is proposed to perform optimization.Reasonable agree...Genetic algorithm(GA)is utilized to design microstrip patch antenna shapes for broad bandwidth.A new project based on GA and high frequency simulation software(HFSS)is proposed to perform optimization.Reasonable agreement between simulated results and measured results of the GA-optimized design is obtained.The optimized patch design exhibits a three-fold enhancement in bandwidth when contrasted with a standard square microstrip antenna,showing the validity of this project.展开更多
基金financially supported by the National Key R&D Program of China(No.2021YFB3502500)the National Natural Science Foundation of China(Nos.51802155 and 51801103)+5 种基金the Natural Science Foundation of Jiangsu Province(No.BK20180443)the"Shuangchuang Doctor"Foundation of Jiangsu Provincethe Aeronautical Science Foundation of China(No.2018ZF52078)the China Postdoctoral Science Foundation(No.2020M671478)the Fundamental Research Funds for the Central Universities(No.NT2021023)a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘Considerable microwave absorption performance at elevated temperatures is highly demanded in both civil and military fields.Single dielectric or magnetic absorbers are difficult to attain efficient and broadband microwave absorption at the high temperature range of 373 K-573 K,and the evolution mechanism of the microwave absorption is still unclear especially for the magnetic absorbers.Herein,ZnO coated flaky-FeCo composite is proposed to break through the bottleneck,which possesses microwave absorption(RL<-10 dB)that covering the whole X band(8.2 GHz-12.4 GHz)at the temperature range of 298 K-573 K with a thickness of only~2 mm.Moreover,attenuation mechanism and evolution of the microwave absorption properties for the FeCo@ZnO flaky material at elevated temperature has been clearly disclosed by the composition and microstructure characterizations,electromagnetic performance measurements and first principles calculations for the first time.Moreover,the Poynting vector,volume loss density,magnetic field(H)and electric field(E)are simulated by HFSS to understand the interaction between EM waves and the samples at different temperatures,further elaborating the attenuation mechanism in high-temperature environment.This study provides guidance in designing and developing high-temperature microwave absorbers for the next generation.
基金This work was supported by the Specialized Research Fund for the Doctoral Program of Higher Education(No.200700130046)the National Natural Science Foundation of China(Grant Nos.60771060 and 60971078).
文摘Genetic algorithm(GA)is utilized to design microstrip patch antenna shapes for broad bandwidth.A new project based on GA and high frequency simulation software(HFSS)is proposed to perform optimization.Reasonable agreement between simulated results and measured results of the GA-optimized design is obtained.The optimized patch design exhibits a three-fold enhancement in bandwidth when contrasted with a standard square microstrip antenna,showing the validity of this project.
