Full implementation of an implicit nonlinear model with memory in an harmonic balance software

This letter describes the mathematical formalism for a full computation of the Jacobian matrix as part of the harmonic balance (HB) technique in the case of implicit nonlinear equations with memory. This new formalism, based on a double Fourier transform of the nonlinearity derivatives versus the time-domain commands, has been developed especially in order to permit the direct coupling of the semiconductor equations of a GaInP/GaAs heterostructure bipolar transistor in a circuit simulator based on the HB analysis technique.