Application Of Maehly To Electromagnetic Scattering From Rough Surface Over A Frequency Band

Method of moments(MoM)is widely applied to simulate the electromagnetic(EM)scattering from rough surface for its high accuracy.However,only one frequency of the incident wave is calculated.To simulate the EM scattering from rough surface over a frequency band,the MoM is time consuming because of the repeated calculations at every frequency.In this thesis,based on the theory of the MoM,the asymptotic waveform evaluation(AWE)technique and the Maehly technology are introduced to study on the EM scattering from rough surface and target over a frequency band.Firstly,the AWE is applied to simulate the EM scattering from two-dimensional(2-D)perfectly electric conductor(PEC)rough surface over a frequency band.Then the Maehly technology is introduced to fast and accurately simulate the EM scattering from 2-D rough surface and with a target over a frequency band.Finally,the Maehly technology is used to simulate the EM scattering from a three-dimensional(3-D)rough surface over a frequency band.Main works of this thesis are as following:1.The fundamental of the MoM and the modeling of the 2-D rough surface are presented.The integral equations and the matrix equations for simulating the EM scattering from 2-D rough surface and with a target are given in detail.2.The fundamental of the AWE technique is shown.The AWE is used to simulate the EM scattering from 2-D PEC rough surface.And to overcome the discrepancy away from the expansion frequency of the AWE,the complex frequency hopping(CFH)technique which has more than one expansion frequency point is applied.Moreover,the influences of the root mean square height and the correlation length of the rough surface and the incident angle on the EM scattering are discussed.3.To overcome the defect of the AWE,such as limited precision in the region far from the expansion frequency point and large computational complexity,the Maehly technology is applied to simulate the EM scattering from a 2-D dielectric rough surface.The accuracy and validity of the Maehly technology are exhibited by comparing with repeated results of MoM at every frequency point.And the Maehly technology is also used to study the properties of EM scattering from a 2-D dielectric rough surface and a target above it.4.The fundamental of the vector electric field integral equation and the modeling of the 3-D rough surface are presented.And the expression of the 3-D tapering wave is shown.The Maehly technology is extended applied to simulate the EM scattering from 3-D rough surface over a frequency band.Influences of the orders of Maehly on the accuracy are presented.