Method of moment modeling of wave scattering from arbitrary geometries in 3-D in free space

In this thesis, wave scattering from electromagnetic (EM) wave – object interaction and radar cross section (RCS) prediction of arbitrary-shaped (conducting or dielectric) objects in three dimensional (3-D) free space is considered. Problem is formulated in terms of volume integral equations containing Dyadic Green Functions. Method of Moments (MoM) is used to the given problem. In the context of MoM, point matching technique is applied. The volume of the scatterer is represented by cubical cells over which the electric field is assumed constant. The electric field integral equation (EFIE) is enforced at the center of each cell to produce a system of equations in a matrix form. Here, the incident field, location, geometry and electrical parameters (relative permittivity and conductivity of the object) of the object are known. The unknowns are the equivalent volume current densities. After obtaining the unknowns of the problem, one can easily derive scattered fields at any given point in the space. This is then used in RCS calculations for both bistatic and monostatic cases. The algorithm developed for this purpose is coded in MATLAB. The model and the algorithm are already validated; here only the code is verified through some canonical tests and comparisons. First, a reference object – sphere – is used. The sphere has analytical exact solution in terms of Mie series summation. Another MATLAB code is prepared for the accurate calculation of the analytical solution. To be able to acquire satisfactory results for a sphere, the size of the cells are smaller than which depends also the values of relative permittivity. Simulations are performed for different material spheres. Simulations of perfectly electrical conducting (PEC) canonical structures are also performed and results are compared with the Transient Solver code of CST Microwave Studio which uses Finite Difference Time Domain.