Application Research On X-band Metamaterial-Inspired Absorber For Qualitative And Quantitative Sensing Measurement

After the second industrial revolution,sensing technology has been vigorously achieved development and has become an important indicator for evaluating the degree of national informatization.It is called the pillar of information technology together with communication technology and computer technology.And the main domains involved are sensors,information management,design,test and manufacture,etc.With the development of science and technology,metamaterial technology is cross-combined with sensing technology,which has become a trend in accord with the country strategic policy.Meta-material is a synthetic material with special property,which has some special physical functions that do not exist in nature.They are mainly used in life,military,and industry,etc.The advantages of electromagnetic meta-material are particularly prominent.They are currently mainly used in radar stealth,absorbent material,optoelectronics,antenna,etc.Due to the bottleneck in detection technology,new technologies are urgently needed to achieve the requirements of non-destructive,non-contact,on-field detection and high sensitivity.Therefore,by designing two metamaterial absorbers in this paper,it realizes fuel qualitative detection and ethanol quantitative detection,respectively,which lays the foundation for the application of metamaterial absorbers in the field of sensing measurement.(1)Research on quantitative detection of ethanol-water mixed solution.Based on the design of double?-shaped structure,the original metamaterial absorber is made,which is arranged in a sandwich-type spatial distribution.It achieves a single-band absorption response in the X-band operating range.By CST software,the resonant structure model and electromagnetic incidence way is studied,which can judge the dependence of the resonant structure parameters and incident angle on the absorption performance of absorber.Then,an equivalent circuit model,can research the relationship between substrate permittivity and resonance frequency,is established through the analysis of absorption mechanism.Those results demonstrate the reliability of the proposed absorber,and provide a fundamental support for quantitative measurement of high dielectric medium.In order to realize non-contact and non-destructive detection,it is necessary to load a microfluidic chip.The study found that its channel parameters can determine the perturbation area.During the test,the phenomenon of injecting ethanol-water mixed solution essentially changes the permittivity of induced electric-field,and achieves different responses that can be characterized by the frequency offset.Because the frequency offset between ethanol and deionized water reaches?f=777MHz,it is important to affirm that the designed absorber has the ability to discriminate medium with relatively high permittivity.Finally,by extracting the measurement inversion model,the proposed absorber has the function of quantitative detection.(2)Research on qualitative detection of fuel oilsBased on the analysis of multi-band and broadband absorbers,the electric field distribution is used to guide the design of resonance structure,and the superposition of multilayer materials is used to design a"candy"type perfect metamaterial absorber.When electromagnetic waves enter the surface of its absorber,the mutual coupling of resonance structure will produce LC resonance,and the absorptivity at the frequency of 10.38GHz is as high as 99.88%,achieving perfect absorption of electromagnetic wave.Through CST simulation software to study the electric field and power loss density,the study found that the energy field at the resonance frequency is the strongest.Based on the micro-strip theory and the syntony circuit analysis,an equivalent circuit model is established,in which its simulation results can study the influence of substrate permittivity on sensitivity compared with CST simulation results.Those results prove that the resonator has a higher resolution for low dielectric constant medium and provides a technical support for loading microfluidic chip.After microfluidic chip is embedded,the proposed absorber loaded with different dielectric media has different sensing responses.When the permittivity of dielectric medium is transformed from 1 to4,the resonance frequencies are 11.32GHz,10.91GHz,10.6GHz,10.355GHz,respectively.And the total offset is as high as?f=965MHz,which proves that the designed absorber has a very high recognition ability for dielectric medium with slight change in dielectric constant.In order to achieve measurement research,it is necessary to build up a qualified test platform and meet the environment without interference factors.The measurement results show that the offsets of kerosene,gasoline#92,diesel,gasoline#95and gasoline#98 after loading into the micro-channel are made of?f_kerosene=365.9MHz,?f_kerosene=365.9MHz,?f_gasoline92=392.6MHz,?f_diesel=400.2MHz,?f_gasoline95=407.8MHz,?f_gasoline98=415.4MHz.Those measurement results meet the qualitative research of five fuel oils by the proposed absorber.