Publication: IEICE TRANSACTIONS on Electronics Publication Date: 2010/08/01 Vol. E93-CNo. 8pp. 1238-1244 Type of Manuscript: Special Section PAPER (Special Section on Heterostructure Microelectronics with TWHM 2009) Category: GaN-based Devices Keyword: Gallium Nitride, power amplifier, switch-mode, efficiency,