Research On Microwave/Infrared Stealth Metamaterial Absorbers With Integrated Microfluidic Channels

Metamaterial absorbers provide a good solution for stealth technology for aircraft,missiles and satellites and the reduction of radar cross-section(RCS).However,with the continuous expansion of the frequency bands required by aircraft,missiles and radars,traditional absorbing materials can no longer meet the requirements of application frequency bands and complex environments,and the multilayer structure of the composite material has the characteristics of high absorption,wide frequency band and light weight.Therefore,a liquid metal broadband microwave/infrared multifunctional metamaterial absorber based on microfluidic technology is proposed.The selection of materials with high temperature resistant flexible substrate material and flexible absorbing structure can carry out threedimensional conformal formation of irregular surface,which has good application prospects in military fields such as missiles and radars.In this paper the absorption characteristics of incident electromagnetic waves in the resonant structural layer and dielectric layer of metamaterial according to the mechanism of electromagnetic wave absorption is studied.The bandwidth is broadened by optimizing the design structure parameters and material eigenparameters,so as to achieve the purpose of flexible three-dimensional conformity.The main work of this article is as follows:(1)An equivalent circuit model based on a multifunctional metamaterial absorber is established,and the functional relationship between different unit structures in the same layer,the functional relationship between different element structures in the same layer,the functional relationship between different element structures in multiple layers and the functional relationship between the unit structure and the microfluidic channel layer are accurately analyzed through the lumped elements R,L and C,and the relationship between the energy loss mechanism and the equivalent circuit between different structures is verified by analyzing the field strength change.(2)A transparent multilayer hexagonal electromagnetic artificial metamaterial broadband absorber based on resistance film ITO was designed,the mechanism of electromagnetic wave absorption was analyzed based on the equivalent circuit model,and the accurate value of the surface impedance of the absorber to achieve high efficiency absorption within a wide range was determined by numerical simulation.At 12GHz-63 GHz,90% absorption of incident electromagnetic waves is achieved.At the same time,the ultraviolet-visible spectrophotometer was used to test its light transmittance,and it was obtained that the light transmittance of the absorber sample was reach about 70% in the visible light band,realizing electromagnetic broadband stealth and optical transparency.(3)In order to further solve the problem that infrared stealth and radar stealth are incompatible,the reaction effect of thermal radiation on electromagnetic metamaterials during the absorption process is analyzed,and a hexagonal double-embedded absorption structure with integrated microfluidic heat dissipation channel is proposed,and a hexagonal multilayer open-closed-loop cross(HMOC)resonator and cross-coupling microfluidic liquid metal structure are used as the absorbing structure and runner structure.It achieves broadband absorption and high-efficiency heat dissipation,and is compatible with infrared stealth function while 5GHz-100 GHz microwave stealth.In the design process,the dielectric materials are made of flexible manufacturing and are thin and light,which meets the conformal requirements of irregular surfaces such as missiles.(4)The microfluidic liquid metal injection process based on MEMS process was designed.According to the fluid dynamics of the liquid metal,the heat dissipation and force of the liquid metal in the microflow channel were analyzed.The structure and size of the microflow channel were determined by simulation,and the processing process was optimized to improve the preparation process of the low thermal resistance fluid channel.Microchannel molds were prepared by photolithography process and deep silicon etching process,and PDMS chip channels were prepared by inverted film process.The PDMS channel was treated with a microelectrode using a particle surface treatment process such as oxygen to complete the bonding.Finally,the microfluidic channel pattern processing of high-viscosity liquid is realized,which solves the key problem that traditional hard materials are difficult to conform.(5)A multi-environment test platform was built,and the stealth function of the absorbing material was verified and analyzed,the absorption performance of the absorbing material was tested,and the polarization and multi-angle incidence performance of the absorber were verified.The infrared test platform was built,and through the infrared test comparison of various types of metamaterial absorbers,it was proved that the purpose of heat release was well achieved by increasing the microcurrent heat dissipation structure,so that the thermal radiation was reduced,and the infrared stealth function of electronic equipment was easily realized.Finally,the main works and research conclusions of this paper are summarized,the innovation points of the research work are sorted out,and the further assumption on the application of the absorber designed in this paper is discussed.