Monotone iterative method for numerical solution of nonlinear ODEs in MOSFET RF circuit simulation

In this paper, we model the metal–oxide–semiconductor field effect transistor (MOSFET) radio frequency (RF) circuit as a system of nonlinear ordinary differential equations. Then we solve them with the waveform relaxation method, the monotone iterative method, and Runge–Kutta method directly in time domain. With the monotone iterative method, we prove that each decoupled and transformed circuit equation converges monotonically. In comparison with the HSPICE outputs, results calculated with our method are stable and robust in both the time and frequency domains. Convergence properties for the monotone iterative and outer iterative loops are also presented and discussed. This method provides an alternative in the time domain numerical solution of MOSFET RF circuit equations.