Publication: IEICE TRANSACTIONS on Electronics Publication Date: 2001/07/01 Vol. E84-CNo. 7pp. 955-960 Type of Manuscript: Special Section PAPER (Special Issue on Techniques for Constructing Microwave Simulators--Design and Analysis Tools for Electromagnetic Fields, Circuits, and Antennas--) Category: Applications of Electromagnetics Simulators Keyword: quasi-optics, grid amplifier, electromagnetic simulation, waveguide, mode converter,