Accurate simulation models yield high-efficiency power amplifier design

The design of RF and microwave power amplifiers continues to be somewhat of an art yet to be reduced to a systematic repeatable design practice on a wide-scale basis, despite the many excellent treatments of the subject in the literature and a number of courses. The general unavailability of sufficiently accurate and reliable nonlinear models for power transistors has been a major factor in limiting the accuracy of power amplifier (PA) simulation results. Suitable nonlinear models must properly treat the nonlinear and combined dc/ac analysis required for proper power compression and efficiency simulation under varied load and bias conditions. In this article, an accurate nonlinear transistor model is shown to form the basis for a systematic simulation-based design procedure for a microwave PA.