The Application Of The Method Of Moment And Its Parallel Computation In EM-Scattering From The Rough Surface And The Target

The dissertation presents systemic theoretical studies for the electromagnetic (EM) scattering by rough surface and complex target using method of moment (MOM) and its parallel computation. The MOM and its parallel computation are exploited to calculate the EM-scattering by 1-D and 2-D rough surface, 3-D complex target, and the composite scattering from 1-D rough surface with 2-D target. The main works are as follows:1. The basic principle of the MOM and the essential knowledge for the parallel computation are firstly introduced. The related theory of the conjugate gradient method (CGM) for solving MOM matrix equation is then given. The concrete procedures of the parallel CGM based on the message passing interface (MPI) of the PC Clusters are shown in detail.2. Using MOM, the EM-scattering characteristics by 1-D PEC and dielectric rough surface are studied. Then the incident tapered plane wave is introduced into the classical Kirchhoff approximation (KA), and the shadowing effect is also taken into account to make the results by the KA have a higher accuracy. Moreover, the scattering problem of the large scale PEC Gaussian rough surface under low grazing incidence is solved by the parallel MOM on MPI of PC Clusters.3. The essential theory for the decomposition of the 3-D complex target and the 3-D vector RWG triangle basis function of the MOM are given. The detailed implementations for discretizing three kind of integral equations, EFIE, MFIE, CFIE for calculating 3-D PEC target EM-scattering by MOM are then shown, especially for the procession of the singular elements of the impedance matrix. The radar cross section (RCS) of a PEC sphere is calculated by the three kind of integral equations, meanwhile, the traits of the integral equations are also discussed. The RCS of the real military targets, a missile and a fighter are calculated by the parallel MOM based on the MPI of the PC Clusters, which are validated by the integrated business software.4. Finite impulse response filter (FIR) theory combined with the fast Fourier transform (FFT) method are firstly applied to generate 2-D Gaussian rough surface, the influences of the roughness parameters on the 2-D Gaussian rough surface profile are discussed. The theory for generating Gaussian beam for calculating 2-D rough surface scattering is then given. The EM-scattering by 2-D Gaussian rough surface is studied by the parallel MOM on PC Clusters. The beam decomposition method combined with parallel MOM on PC Clusters is applied to solve larger scale 2-D rough surfaces EM-scattering problem.5. The composite EM-scattering of 1-D rough sea surfaces with a 2-D low flying missile and floating ship on it are studied by MOM when the incident wave is vertical polarized, the influences of the parameters on the composite scattering characteristic are discussed in detail. Using parallel MOM on PC Clusters, the composite scattering characteristic of 1-D large scale PEC rough surface with a PEC cylinder on it are researched, a series of useful conclusions are also obtained.