Applications Of The On-surface Discretized Boundary Equation Method To Problems Of Scattering By Perfect Conducting Cylinders

In this thesis, the on-surface discretized boundary equation (OS-DBE) method is modified and expanded to solve several kinds of problems of scattering by perfect electric conducting (PEC) cylinders.The OS-DBE method is modified to solve the two-dimensional scattering problems of PEC cylinders with electrically large concave parts. It deals with the convex and concave regions separately. For the convex part, the conventional OS-DBE method is used to calculate the current distribution point by point. Then for the concave part, the modified OS-DBE method is used to calculate all the current distribution in only one operation with the whole concave area filled with basis functions and field points. This step will use the current distribution of the convex part which has been calculated. The modified OS-DBE method can solve electrically large concave objects efficiently.For the objects with deep cavities, multiple bounces of the waves in the cavities will lead to large iteration numbers. The modified OS-DBE method is combined with the near-resonance decoupling approach (NRDA) to analyse such kind of two-dimensional scattering problems. The cavity is separated into several sections, and the moment method combined with a connection scheme is used to obtain the generalized admittance matrix which relates the electric current and the magnetic current on the aperture. The NRDA can significantly reduce the iterative number. Benefiting from this, the modified OS-DBE method combined with the NRDA can reduce the total computation time.The OS-DBE method and the modified OS-DBE method combined with the spectrum of two-dimensional solutions (S2DS) are used to solve the three-dimensional problems of electrically large PEC convex and concave cylinders illuminated by arbitrary plane waves.