When using Vector Network Analyzers (VNAs) to evaluate backplane and interconnects, one of the most basic considerations is the frequency range over which to make S-parameter measurements. The choice of frequency range affects the ability to locate defects, the correlation between simulations and measurements, and ultimately the ability to make good decisions concerning cost/performance trade-offs. This white paper discusses the importance of both high and low frequency test limits and also their impact on your time domain results.