Theoretical facet and experimental results of harmonic tuned PAs

High-efficiency power amplifier design criteria imply a synthesis of input and output networks with particular emphasis on their harmonic behavior. In this article, a simplified approach to clarify the relevance of such terminations is presented. Starting from the implications of power balance for stage performance, design criteria to improve the efficiency of high-frequency applications are presented. In order to validate the approach, comparisons among the performances of single-stage amplifiers, all operated at 5 GHz under a sinusoidal driving signal and synthesized by utilizing different design methodologies, are presented. Drain efficiencies at 1-dB compression of 44.5%, 53.3%, and 61.56% have been measured respectively for the tuned load and harmonically manipulated (2(nd) and 2(nd) & 3(rd)) realized amplifiers, compared with a simulated drain efficiency of 55% using the Class E approach. (C) 2003 Wiley Periodicals, Inc.