Fast simulation method for a transient analysis of lossy coupled transmission lines using a semi-analytical recursive convolution procedure

A fast method for a transient time domain analysis of lossy coupled transmission lines characterized by frequency independent primary transmission line parameters is presented. The transmission lines are represented by the model of delayed current components and, therefore, this model can be integrated very easily into existing analogue simulators. The elements of the most significant model quantities, the current transfer matrix and the characteristic admittance matrix, are approximated in frequency domain by a Pade approximation in order to obtain explicit expressions which can be transformed analytically into the time domain. These time domain functions are given by weighted and delayed exponential functions and dirac impulses. Due to these types of functions, a semi-analytical recursive convolution algorithm is applied in order to speed up significantly the time-consuming numerical ordinary convolution. This leads to very short computation times which increase solely linearly with the total simulation time.