In recent years, there has been a substantial increase in the use of active devices operating at mmWave and sub-terahertz frequencies. Such devices find applications in various industries including automotive, radar, radio astronomy, remote sensing, military and others.

Measuring S-parameters has always been an accepted way to characterize these devices. We will have a look at how VNAs are used to characterize these DUTs for linear frequency converting and non-frequency-converting applications.

As the devices start to be driven into the non-linear regions, standard S-Parameters are not enough for a complete device characterization, and new techniques need to be used.

We will examine techniques that measure S-parameters at user-specified power levels, discuss making accurate and repeatable gain compression measurments, as well as non-50 ohm active load-pull measurements on DUTs under large signal conditions which make validating non-linear device models possible, and how to create ideal matching networks to maximize DUT performance.