Periodic steady-state analysis of coupled ODE-AE-CGE systems for MOS RF autonomous circuit simulation

This paper studies the steady-state analysis of a system of ODE-AE-CGE (ordinary differential equations - algebraic equations - current generate equations) arising from simulation of MOS RF autonomous circuits in which the transistor acts as a current generator and its current equations could adequately represent the transistor large-signal dynamic behavior. Gauss-Seidel relaxation is applied to decouple the system so that the shooting method, which is used to find the periodic steady-state response, can be performed with a low-order sensitivity matrix. This simplifies the solution process and results in a fast algorithm. We illustrate the new algorithm with the simulation of a typical voltage-controlled oscillator (VCO), the simulation results show good agreement with those obtained by MEDICI, a device simulator.