摘要
设计了一种基于介质谐振器的水基微波吸波器。介质谐振器包括两个长方体介质板和一个十字形空腔,并在其内部充满水以实现宽带微波吸收效果。不同于传统水基超材料中相互独立的水基单元,本设计中十字形空腔所形成的水流通道横截面面积达到3 mm×3 mm,可确保阵列中水流畅通,因此该结构满足水冷工作要求,可实现大功率微波的无衰减吸收。仿真结果表明,在21.8~35.9 GHz的微波频段内,吸波器对入射电磁波的吸收率大于90%,相对吸收带宽为48.9%。此外,该吸波器对入射波的偏振不敏感,在宽频段范围内对大入射角电磁波仍有高吸收效果。通过3D打印技术实现了样品加工,实验结果与模拟结果吻合良好。该吸波器在宽带大功率微波吸收领域有较大的应用潜力。
Objective Metamaterial microwave absorbers are widely used in many fields,such as radars,stealth technology,electromagnetic compatibility,anti-electromagnetic interference,and sensors.To increase their usability,the functional requirements of absorbers have been also improved,including not only the broadband absorption properties but also wideangle absorption characteristics.Furthermore,polarization insensitivity is now required,while all-dielectric metamaterials absorbers show unique potential in improving impedance matching in wide band.It is interesting to note that water,as an abundant natural resource on earth,possesses a high dielectric constant and large dispersion,which is of great significance for all-dielectric absorber applications.In addition,most of the water-based absorbers proposed in the literature cannot circulate the aqueous solution between the cells,or the cross-sectional area of the water flow channel of the adjacent cells is too small.The fact that most of the microwave energy absorbed by water-based metamaterials is converted into heat,if the water itself cannot circulate and dissipate heat,indicates the accumulated heat will seriously deteriorate the working performance of the absorber.However,if a water-based resonant cell with a larger crosssectional area of the water flow channel is designed,the aqueous solution can be circulated both inside and outside.Hence,the generated heat can be efficiently dissipated during high-power microwave absorption.Methods First,a microwave absorber based on a water-dielectric resonant structure is designed.More specifically,the resonant cell mainly comprises a cruciform water cavity and its respective encapsulation structure.The absorption spectrum of the model is simulated under different polarization angles and incident angles using the finite element method.Moreover,the electromagnetic wave absorption mechanism of the absorber is systematically studied through the distributions of the electric and magnetic fields and power loss density distribution.The array structure consisting 25×25 cells is processed by the 3D printing technology.The extracted electromagnetic wave absorption characteristics of the samples under different polarization angles and incident angles are tested using the free space method.Furthermore,the comparison and analysis with the simulated results are performed.Results and Discussions In this study,an all-dielectric water-based microwave absorber is proposed(Fig.1).The array structure consisting 25×25 cells is processed by the 3D printing technology,and the acquired absorption characteristics of the absorber are experimentally investigated by the free space method(Fig.2).Both the simulated and experimental test results reveal that the absorptivity of the absorber is greater than 90%in the microwave broadband frequency of 21.8--35.9 GHz(Fig.3).The simulated relative impedances of the water-based absorber are approximately equal to the free space impedance in the operation frequency range,which provides the wideband absorption with high absorptivity(Fig.4).The electric field,magnetic field,and power loss density at resonant frequency are simulated,and the water layer plays a key role in wideband absorption(Fig.5).The effects of both the structural parameters and the channel cross-sectional areas on the electromagnetic wave absorption spectrum are also simulated and analyzed(Figs.6 and 7),and the results provide an important reference for optimizing the structural model.The absorption performances of the absorber at different temperatures are analyzed,and the results suggest that the absorptivity of the absorber is almost insensitive to water temperature changes(Fig.7).Next,the absorption of the structure at different polarization angles is investigated,and both the simulated and experimental results show that the absorber is insensitive to polarization angles(Fig.8).Finally,the absorption spectra of the proposed absorber at different incident angles for transverseelectric and transverse-magnetic polarizations are analyzed.The experimental results validate that the structure can maintain wideband absorption at wide incident angle ranges(Figs.9 and 10).Conclusions A microwave absorber based on a water-dielectric resonator is designed.Simulation results reveal that the absorber can achieve electromagnetic absorptivity of more than 90%in the frequency range of 21.8--35.9 GHz,while the relative absorption bandwidth is 48.9%.Compared with the water-based cells that are not connected to each other in the configuration of the traditional water-based wave-absorbing metamaterials,the cross-sectional area of the water flow channel formed by the cruciform cavity in this structure can reach 3 mm×3 mm.As a result,the water-cooling working condition of the absorber can be addressed,and it can be applied to high-power microwave absorption occasions.In addition,the proposed structure possesses polarization-independent absorption characteristics and also operates well on broadband absorption under wide-angle incidence.The absorber sample is processed by the 3D printing technology,whereas the electromagnetic wave absorption characteristics of the sample under both different polarization and incident angles are explored by the free space method.Interestingly,the test outcomes are in good agreement with the simulation results.Our work therefore provides a practical solution for the enhanced broadband absorption of high-power electromagnetic waves.
作者
邓光晟
陈文卿
余振春
杨军
尹治平
Deng Guangsheng;Chen Wenqing;Yu Zhenchun;Yang Jun;Yin Zhiping(Special Display and Imaging Technology Innovation Center of Anhui Province,Academy of Opto-Electronic Technology,Hefei University of Technology,Hefei 230009,Anhui,China;Anhui Province Key Laboratory of Measuring Theory and Precision Instrument,School of Instrument Science and Optoelectronics Engineering,Hefei University of Technology,Hefei 230009,Anhui,China)
出处
《中国激光》
EI
CAS
CSCD
北大核心
2022年第21期69-76,共8页
Chinese Journal of Lasers
基金
国家自然科学基金(61871171)
航空科学基金(2020Z0560P4001)
中央高校基本科研业务费资助项目(JD2020JGPY0012)。
关键词
材料
超材料
吸波器
宽带
大功率
水基介质
materials
metamaterial
absorber
broadband
high power
water-based medium
