Nonlinear, Transient Simulation of Distributed RF Circuits using Discrete-Time Convolution

High frequency circuit simulation involving nonlinear active devices presents special simulation challenges because of the complex distributed linear environments involved, and the increasing need to accommodate wide-spectrum digitally-modulated signal formats operating over very large bandwidths. This contribution describes a simulation approach that is based on discrete-time convolution which allows both transient and steady-state solutions to be obtained with high accuracy, generality and robustness. Examples are given of the application of this kind of simulation to severely nonlinear operation of a high frequency power amplifier employing lumped elements with lossy, dispersive transmission lines. The approach described is also of interest for signal integrity simulations in high speed digital systems.