New Time-Domain Preconditioners for HB Jacobian of RF Circuits

Harmonic balance (HB) method is a powerful frequency-domain method used in RF circuit simulations. The key point of HB method is efficiently solving the Jacobian system in Newton’s method. In this paper, we first introduce a new time-domain preconditioner for HB Jacobian. Unlike existing time-domain preconditioners, which cannot balance the efficiency of solving the linear system corresponding to the preconditioner with the reduction in iteration step for strongly nonlinear circuit, the proposed preconditioner successfully addresses both aspects. We also present a new preconditioning method that extends time-domain preconditioners to circuit with distributed devices, which was previously unattainable. Finally, a matrix norm-based metric is proposed to measure the strength of circuit nonlinearity, which can help us a priori choose the appropriate preconditioner.