In this issue of SI-Insights, we describe a methodology for evaluating the accuracy of a transmission line simulation tool and apply it to the Polar Instruments Si9000. We show the pitfalls of the traditional, “build a test line and measure it” approach. When this new methodology is applied to the Polar Instruments Si9000 tool, it is found to be accurate to within 2% up to at least 10 GHz. The approach presented here can be applied to many other simulator tools as well. This is a condensed version of the full app note, BTS106_Si9000_Simulator_Accuracy_AppNote.pdf, available on www.beTheSignal.com