Software Defined Radio and Cognitive Radio will revolutionize wireless communications. Consequently, commercial, governmental, and academic organizations around the world face daunting technical challenges. This book provides detailed knowledge of modern RF signal processing power amplifiers, which constitute an enabling technology for the new world of multiband, multimode phones, and networks. It presents detailed discussions of SDR, cognitive, and opportunistic spectrum usage, as well as RF vector combining. The author also offers an in-depth analysis of selected circuits and examines both new and existing system requirements. The text also includes a CD-ROM that contains select examples.