A Novel Time-Domain Modeling Technique Based on the S-Parameter for Microwave/RF Components in System-Level Simulations

This paper proposes a novel time-domain modeling technique based on S-parameters to overcome the modeling challenges of microwave/RF components for system-level simulation of broadband electronic systems. Directly incorporating traditional circuit-level frequency-domain models into the time-domain signal flow driven system-level simulations requires repeated time-frequency transformations, which significantly degrades computational efficiency. To address this limitation, the proposed technique treats the S-parameter defined components as FIR digital filters and transforms the frequency-domain S-parameter model into a time-domain FIR model, where the FIR is meticulously designed to match the frequency response specified by the original S-parameter. Furthermore, an adaptive approach combining the frequency sampling method and the PSO algorithm has been developed to determine the optimal order of the FIR to balance modeling accuracy and computational efficiency. The proposed method performs convolution and delay correction on the signal in the time-domain and eliminates the need for frequent time-frequency transformations. Simulation results demonstrate that the proposed technique effectively achieves an optimal balance between modeling accuracy and computational efficiency, providing an effective solution for constructing system-level simulation models for microwave/RF components.