Abstract: A novel finite-difference time-domain(FDTD) modeling method for arbitrary linear lumped networks is presented. First, the admittance parameters in the frequency domain of the lumped networks are expressed as a summation of several rational fractions, which are converted into those in the time-domain by means of the inverse Fourier transform(IFT) technique. Then, the piecewise linear recursive convolution(PLRC) method is proposed, the admittance parameters in the time domain are incorporated into the FDTD updated equation directly with the aid of the method. Compared with the modeling methods based on Z-transformation, the proposed algorithm needs fewer variables, preserves the explicit nature, and keeps the same computation accuracy as well. Finally, the method is applied to model some one-, and two-port micro-strip transmission line networks, and simulation results agree well with those obtained by the modeling method available based on Z-transformation.

Key words: finite-difference time-domain, lumped networks, piecewise linear recursive convolution