RF/Microwave Amplifier Design Using Harmonic Balance Simulation With Only S-parameter Data

It is widely held that S-parameters combined with harmonic balance (HB) alone cannot provide for the simulation of the power performance of transistors. This article describes a method for designing and simulating amplifiers within NI AWR Design Environment™ for maximum power using HB simulation when the only available data is the S-parameters of the transistors. The method is widely applicable when nonlinear transistor models are not available and can also be very helpful even when the nonlinear models are available. The topic is an extension of Steve Cripps’ Load-Line Approach, which was developed further with the power parameters introduced by Pieter Abrie. These techniques may be used to create useful approximations that allow HB simulation with transistors that do not have nonlinear models.