Circuit Simulation of Structures with Distributed Parameters

Resumo

The possibility of using equivalent circuits of well-known morphology for simulation of structures with distributed parameters in the frequency and time domains is considered. Special attention is paid to the Π-circuit and to the class of circuits intended for ultrabroadband simulation. The parameters of the circuits were obtained based on the measurements of frequency responses of the structures with further approximation of the measuring results. It is noted that all known equivalent circuits except the Π-circuit are oriented for simulation in the frequency domain. The error of simulation using the Π-section was studied, and it was revealed that using it for ultrabroadband simulation is inadvisable. However, in the time domain, the Π-section provides exact (by Elmore) simulation of the delay time and a negligible error of simulation of the rise time; in particular, when simulating a conductor (a microstrip line) loaded with its characteristic impedance, the Π-section exactly (by Elmore) simulates both the delay time and the rise time; i.e., the relative error of rise time simulation equals zero both for noninductive lines (resistors) and for lines without resistance loss.