Millimeter Wave Radiation Model Research Of Multi-layer Composite Material

With the advance of detection and anti-detection technology,target materials are gradually developing towards multichannel-stealth compatibility.The target's surface is usually coated with multilayer composite material to effectively avoid the detection and tracking of each band.As a new means of information acquisition,millimeter wave passive detection can be an effective complement to other methods.Different targets have different radiation characteristics,which is the theoretical basis of passive detection with millimeter wave radiometer.As the basis of passive detection,it is of great significance and value to carry out theoretical and experimental research on the millimeter-wave radiation model.The main work of this paper is to carry out the relevant theoretical research and experimental verification about the radiation model of multilayer composite material in the millimeter wave band.Firstly,the basic theory of millimeter wave radiation is summarized,and the radiation model with uniform medium profile distribution,the coherent and noncoherent radiation model with nonuniform medium profile distribution are also analyzed respectively,which is the theoretical research basis of this paper.Then,the equivalent electromagnetic parameters inversion method of multilayer composite material is studied.A inversion method of equivalent single-layer electromagnetic parameters for multilayer composite material is proposed,which is based on nonlinear least squares fitting.It provides a simplified approach to the research and application of multilayer composite material's radiation model.Next,in order to accurately obtain the complex permittivity and complex permeability of the coating material in the relevant band.Based on the theory of free space method,the S-parameter to electromagnetic parameters theoretical model of coated flexible materials is deduced,and the results are verified by related experiments.Finally,the arch method system is used to measure the emissivity of different materials with different incident angles and different polarization modes.The results of the radiation model are compared with the experimental data to verify the accuracy of millimeter wave radiation model and the equivalent electromagnetic parameter inversion method.