| With the ever-increasing density of integrated circuits, interconnect consisting of parallel conductors embedded in dielectric media becomes a dominating factor in determining circuit performance. In order to guarantee circuit performances, interconnect effects such as reflection, dispersion, attenuation and crosstalk have to be modeled accurately.; Among the interconnect models, the most reliable lossless model is the Branin's method of characteristics. It has been generalized to model lossy interconnects. With this model, circuit simulation including interconnect effects, which are usually characterized in frequency-domain, can be simulated consistently in time-domain with active, nonlinear devices. Although methods to extract the characteristic models are developed, they are iterative methods. In addition, for the coupled interconnect model extraction, they use even-mode and odd-mode excitation. In this way, two measurements or full-wave simulations are required.; In this thesis, a direct method to extract the time-domain generalized characteristic model for microstrip interconnects in high-speed circuits is presented. The method proposed uses discrete-time numerical convolution, deconvolution and self-convolution root to calculate the characteristic impedance and propagation function directly from the terminal responses obtained by the FDTD simulation. For the characterization of a coupled interconnects, model extraction from the terminal responses obtained by a single FDTD simulation is achieved by exploring signal propagation delays among ports.; Accurate full-wave FDTD solver with the state-of-the-art perfectly matched layer modified for inhomogeneous microstrip circuit is developed to obtain the port-voltages for the extraction of parameters and verification of the generalized characteristic model.; The relation between the scattering parameters and the generalized characteristic model are derived from signal flow graph so that microwave components described by the scattering parameters can be incorporated in the time-domain simulation process and scattering parameters can be obtained from the generalized characteristic model.; Extensive application examples including resistor and capacitor terminations, nonlinear diode termination and resistor-transistor-logic NOR-gate termination are given to demonstrate the efficiency and accuracy of the model. Comparison with the direct full-wave FDTD simulation substantiates the validity of the models. |
