On the Performance of True-Differential/True-Mode Stimulus Methods at Higher MM-Wave Frequencies

Certain devices, including differential multipliers, may require simultaneous drive on two (or more) ports with a controlled phase relationship as can measurements such as differential gain compression. While these measurements have been done for many years, there is some increased interest in a better understanding of accuracy/sensitivity for mm-wave implementations. An assessment using a representative broadband VNA construct for calibration sensitivity and the effects of LO drift has been performed. Modified methods of managing these aspects were found to improve drive phase accuracy by a factor of two in some cases.