System identification and model order reduction for TLM analysis of microwave components

A System Identification (SI) and Prony's model based algorithm for the modelling and prediction of a time- domain transient response is introduced and applied to time- domain Transmission Line Matrix (TLM) transient responses in order to extrapolate parameters of microwave circuits and accelerate the simulation process. Application of moment matching Model Order Reduction (MOR) techniques to the TLM method is presented with empha- sis placed on Krylov subspace methods based on Lanczos process and its modifications. The Krylov subspace methods are attractive for MOR in the TLM framework because the construction of the orthonormal and biorthogonal bases used for the Krylov subspaces can be carried out through the direct application of the implicit TLM solver. MOR applied to the TLM method allows to generate a compact macromodel of the TLM-system and reduce the computational time. The advantages of the SI and MOR techniques and their comparison are demonstrated trough their applications to the analysis of a planar patch antenna.