FDTD Modelling of RF Circuits Based on Lumped Components and Transmission Lines Using Modified Telegrapher's Equations

This paper reports for the first time a finite-difference time-domain (FDTD) method to model discrete lumped L, C components and RF circuits in general by modifying the Telegraph equations of the transmission line (TL) equivalent. The proposed equations enable the modeling of circuits that comprise of lumped-element components and TL and can be exploited for the realization of a variety of RF circuits. Two test case scenarios are shown as examples, a 2
^nd
order bandstop filter and a 3
^rd
order bandpass filter. The results are validated by obtaining S-parameters for the circuits and matched against ADS.