Nonlinear network analyzer measurements for better transistor modeling

In today's RF applications, silicon technology is more and more competing with its III/V counterpart. This means that MOS (LDMOS) and bipolar (HBT) transistors are operated under large signal conditions, handling time-domain signals with amplitudes in the range of Volts, while the transistor modeling was usually performed conventionally with just small-signal excitation in the Milli-Volt domain, i.e. using S-Parameters measured by a Vector Network Analyzer (VNA). With the availability of Nonlinear Vector Network Analyzers (NVNA), measurements of transistor spectra with magnitude and phase can be made easily. And this permits to extend device modeling also into the more realistic large-signal RF (Radio Frequency) domain. This new measurement and modeling domain therefore leads to improved compact models and improved modeling strategies.