Publication: IEICE TRANSACTIONS on Electronics Publication Date: 2001/07/01 Vol. E84-CNo. 7pp. 967-972 Type of Manuscript: Special Section LETTER (Special Issue on Techniques for Constructing Microwave Simulators--Design and Analysis Tools for Electromagnetic Fields, Circuits, and Antennas--) Category: Keyword: object-oriented design, electromagnetic field simulation, hybrid scheme, FDTD,