Strong Perturbation Theory To Calculate The Effective Electromagnetic Parameters Of The Iron Fiber Coating

Iron fiber mixed with resin is a new kind of radar absorbing material(RAM), it has super characteristics in many aspects than traditional RAM, and is called a new generation RAM. The interest of iron fiber mixture began at 90 decade last century, since then in our country, the scientists pay great attention to the researching work for its absorbing characteristics and manufacturing methods. But how to predict its reflected characteristics and equivalent Electric and Magnetic (EM) parameters from components of the mixed material containing iron fibers, and how to make sure absorbing material's components from the required reflected characteristics, still hasn't a viable method and calculating program. The purpose of this paper includes three contents. One is to research a method that we can calculate the oriented iron fiber mixture's EM parameters from it's components. The second is to afford applied computer program. The last is to analyze the relation between mixture's EM parameters and iron fiber's figure and content, and get some disciplinary conclusions.This paper uses the Strong Fluctuation Theory (SFT) as analysis tool. First ,we study how apply this method to the iron fiber mixture, and recognize it can be applied for this purpose only if the EM parameters of the single electric fiber be obtained. Second, because dyadic Green function's singularity great effects the integral equation in SFT, we resolve the calculating problem of the coefficients of singular dyadic Green function. At the last, we design program for searching the required EM parameters of the mixture. The obtained formula are coupling equations, it is impossible to use traditional numerical value's methods, so we suppose to use genetic algorithm toprogramme and to search the required results.Based the calculating numerical values, a serial of analysis of the rules of the EM parameters depending upon the long-radius ratio, radius of the fiber, the volume ratio, etc are performed. The rules can summarize one point: the long-radius ratio, radius and the volume ratio of iron fiber's have remarkable effect to mixture's equivalent permittivity and magnetic permeability. We prepare some samples of iron fiber absorbing material, and compare calculating and experimental results. It is proved that the calculation method is reliable.From above, absorbing material can satisfy the requirement of less proportion, wider frequency scope and better absorbing effect at the same time if only the appropriate original parameters are chosen . Simultaneity, the analysis of single oriented iron fiber mixture is the foundation of resolving oriented multiply iron fiber absorbing material. The reflected characteristics and equivalent EM parameters of arbitrary number of plies can be obtained through translation matrix. The diagrams of this paper can be used for obtaining the equivalent EM parameters with any mixed ratio, and some of rules have great value of reference for designing absorbing material.