Unconditionally Stable ADI–BOR–FDTD Algorithm for the Analysis of Rotationally Symmetric Geometries

In this letter, the alternating-direction-implicit (ADI) technique is applied to the body of revolution finite-difference time-domain (BOR-FDTD) method, resulting in an unconditionally stable ADI-BOR-FDTD. It inherits the advantages of both ADI-FDTD and BOR-FDTD methods, i.e., not only eliminating the restraint of the Courant-Friedrich-Lecy condition, with an efficient saving of CPU running time, but also leading to a significant memory reduction in the storage of the field components. To overcome the singularity, a special treatment is made along the vertical axis of the cylindrical coordinates. Numerical results are presented to demonstrate the effectiveness of the proposed algorithm