Applied Research, Based On Efficient Modeling Method Of The Broadband Electromagnetic Scattering

In recent years, wideband electromagnetic scattering has been in urgent demand in such fields as ultra-wideband, SAR, target recognizing, and etc. A fast, accurate, stable and efficient method is urgently needed that can simulate and analyze the wideband electromagnetic scattering.Currently there are three ways of calculating wideband electromagnetic scattering: frequency-domain method, time-domain method and extrapolation in time and frequency domains. Through analyses and experiments, this paper presents the strength and weakness of each method in terms of computing time, memory, stability and accuracy.The method of frequency-domain uses mainly the combination of MOM and FFT. With the progress of R&D on FMM and MLFMA, the frequency-domain method is able to be further developed. It can now be applied in the calculation of electrically large targets. The second part of this paper uses frequency-domain method to calculate and compares it with the result of the time-domain method, thus proves its accuracy and effectiveness. It even provides a quite practicable way to calculate wideband electromagnetic scattering of complex electrically large targets.In traditional calculation, it is required that calculation targets should scatter among spots of different frequency, which would give rise to an enormous amount of computing when the question is for wideband electromagnetic scattering. This could be effectively solved by using the interpolation method in computational electromagnetic. In its second part, this paper looks into various efficient techniques of interpolation and extrapolation, which are now widely applied, such as AWE, MBPE, normalized induced current interpolation, and etc. They have integrated some physical properties of computational electromagnetic, getting the slowly varying factors, and therefore receive desirable results when applied in wideband calculation. They can substantially reduce the amount of computation with a certain degree of accuracy guaranteed. This paper researches into and analyzes the application of these methods within the field of wideband, and discusses their special characteristics and their scope for application. The method to calculate wideband electromagnetic scattering of complex electrically large targets has been in urgent demand. This paper utilizes highly-efficient calculation methods in computational electromagnetic. It draws on the principle of scattering centre, proposes an approach of interpolation in frequency-domain. The method is based on scattering centers model, and the parameters are obtained via ESPRIT. What makes it different from traditional radar imaging is that the scattering field is no longer measured, but is calculated by efficient electromagnetic methods. This paper not only verifies the effectiveness of the said method in wideband electromagnetic scattering, but also improves and optimizes the ESPRIT method according to computing computational electromagnetic in order to better suit the model.This paper is motivated by pressing engineering need and provides a practicable approach for wideband electromagnetic scattering of complex electrically large targets by experimental verification. It also researches into the interpolations for simple targets, proposes a method for complex targets, and further improves the calculating system of wideband electromagnetic scattering.