On the solution of a class of large body problems with full or partial circular symmetry by using the finite-difference time-domain (FDTD) method

This paper presents an efficient method to accurately solve large body scat tering problems with partial circular symmetry. The method effectively redu ces the computational domain from three to two dimensions by using the reci procity theorem. It does so by dividing the problem into two parts: a large r 3-D region with circular symmetry, and a smaller 2-D region without circu lar symmetry. An finite-difference time-domain (FDTD) algorithm is used to analyze the circularly symmetric 3-D case, while a method of moments (MoM) code is employed for the nonsymmetric part of the structure. The results of these simulations are combined via the reciprocity theorem to yield the ra diation pattern of the composite system. The advantage of this method is th at it achieves significant savings in computer storage and run time in perf orming an equivalent 2-D as opposed to a full 3-D FDTD simulation, In addit ion to enhancing computational efficiency, the FDTD algorithm used in this paper also features one improvement over conventional FDTD methods: a confo rmal approach for improved accuracy in modeling curved dielectric and condu ctive surfaces, The accuracy of the method is validated via a comparison of simulated and measured results.