High-power devices are common building blocks in RF and microwave communication systems. One such device, the high-power amplifier, plays an especially critical role in today’s mobile phones, base stations for cellular and mobile wireless infrastructure and satellite communication systems. In the base station market, for example, high power amplifiers approaching 100 watts are typical. To obtain the most power from these devices, engineers are forced to push them to their limit, often driving them into the nonlinear region of operation. Such nonlinear behavior can be problematic to the amplifier and is typically a contributing factor in wasted frequency spectrum in communication applications. Accurately characterizing and understanding this behavior is critical to enabling today’s engineer to design and verify efficient high-power devices like amplifiers.