A Study On Computation And Prediction System Of Multi-Phase Media Effective Electromagnetic Parameters

Materials design originated from exploring and utilizing materials. The higher requirement was put forward in researching and exploring materials with the development of science and technology. Experiential and half experiential research methods can' t meet the requirement any longer because them have wasted much resource, manpower and time. Materials design have transformed from simply selecting materials to using modern materials design theory, computing technique and basing on materials usage, performance and manufacturing methods and techniques to design required materials. Then, the design question of new materials was solved in theory and new system of estimation, prediction and controlling materials performance was founded.Stealth technology appeared in the World War? and had more than 50 years history. Every kinds of weapon would face the tightly threat in future with the rapidly developing electronic technology. Stealth technology was regarded as a efficiency methods of improving the survival and breakthrough power of weapon. However, the key to develop stealth technology is developing and applying stealth materials. Radar absorbing materials is the rapidest developing materials in stealth materials. It can reduce the possibility of being found by radar because it can minish the radar cross section of theaircrafts, missiles, naval ships and tanks. Radar absorbing materials can be divided into coated absorbing materials and structured absorbing materials by molding techniques and bearing weight. All of them are the multi-phase medium. The effective electromagnetic parameters are the imperative data to compute design absorbing materials.In the paper, we adopt the strong fluctuation theory to research in predicting the effective electromagnetic parameters of DT-50 which represent coated absorbing materials and the effective electromagnetic parameters of fiber fabric which represent structured absorbing materials are abroad applied in manufacturing stealth aircrafts and ships. Considering about the anisotropy of structure, we adopt the strong fluctuation theory to solve the plural integral equation about electromagnetic of materials. At last, we design a program to search the solution.Comparing the computation results with the experimental results, we find strong fluctuation is an efficiency methods to compute the effective electromagnetic parameters of coated absorbing materials and structured absorbing materials. In the same frequency, the effective electromagnetic parameters of coated absorbing materials are linearly varying with the occupied volume of absorbent. In the same occupied volume, the permittivity of coated absorbing materials appeared maximum about latent frequency and permeability are monotone varying with frequency. The relation of the effective permittivity ofstructured absorbing materials is more complicated than coated absorbing materials, but appeared maximum mainly about latent frequency. We can assumablely judge the curve of reflectivity to frequency and estimate performance of absorbing materials with computing results of the effective electromagnetic parameters in different frequency. With computing results, we can select materials to meet demand and reduce materials design works too.