Design of Broadband High-Efficiency Power Amplifier Through Interpolations on Continuous Operation-Modes

Besides various kinds of continuous-mode high-efficiency power amplifiers (HEPAs), there do exist many other undefined HEPA operations. In place of introducing variables into waveform equations, a numerical mode-interpolation method based on the nonlinear drain current calculations is used in this paper. The combinations of fundamental drain voltage's amplitude and phase boundaries from general continuous modes are used to form the interpolation grids. The interpolated high-efficiency operations determined by the practical transistor's characteristics are collected as perturbation seeds in a solution expansion procedure. Hence, the expanded optimized load impedances are defined as a candidate design space of a mixed-mode HEPA. A broadband HEPA design example from 0.5 to 4 GHz is given based on these interpolated impedances. Finally, this PA is fabricated and measured to offer 39.0- to 42.3-dBm power and 58.2% to 69.3% drain efficiency from 0.45 to 4 GHz.