A combination of FD-TD and Prony´s methods for analyzing microwave integrated circuits

In applying the FDTD (finite-difference-time-domain) technique to analyze microwave integrated circuits, the transient time record required for the Fourier transforms to obtain accurate frequency-domain scattering parameters can be up to tens of thousands of iterations. Depending on the complexity of the microwave integrated circuit being analyzed. which dictates the size of the spatial sampling grid to be used in modeling the physical structure, the computation time can be several hours. It is shown here that the accuracy of the scattering parameters is compromised if the transient time record is terminated too early. It is demonstrated that the required long FDTD time record can be obtained from a relatively short FDTD time record by using Prony´s method.<>