Systems and methods for determining a value of a variable on a radio frequency (RF) transmission model are described. One of the methods includes identifying a complex voltage and current measured at an output of an RF generator and generating an impedance matching model based on electrical components defined in an impedance matching circuit coupled to the RF generator. The method further includes propagating the complex voltage and current through the one or more elements from the input of the impedance matching model and through one or more elements of an RF transmission model portion that is coupled to the impedance matching model to determine a complex voltage and current at the output of the RF transmission model portion.