Finite-difference time-domain analysis of pulse propagation in multichip module interconnects

The application of the finite-difference-time-domain (FDTD) method to the electromagnetic characterization of multichip-module (MCM) interconnects with perforated (mesh) reference planes is demonstrated. The limitations of the method in finding transmission line propagation characteristics (i.e., characteristic impedance Z₀ and phase constant β) are investigated. An alternative approach for the characterization of MCM interconnects which exploits the capabilities of the FDTD method is suggested. This alternative approach uses the results from the FDTD method to extract the per unit length delay and approximate impulse response of the system. These results can be used to identify the effects of the perforated reference plane on signal propagation. The validity of the TEM approximation for signal propagation in realistic MCM structures is also examined