Automatically Controlled Coverage of the Voltage Plane of Quasi-Unilateral Devices

We developed a systematic procedure to efficiently cover the (V1, V2) voltage plane of two-port microwave devices. The method is restricted to (quasi-)unilateral devices, because we assume that the V1(t) does not change when applying an additional a2 travelling voltage wave. By choosing the adequate magnitude and phase of this a2 signal, the V2 of interest can be constructed. We illustrate this method on a HEMT and show that, for the used experimental conditions, only 27 vectorial large-signal measurements are sufficient to cover the (V1, V2) operating region of the device. This is a significant reduction in the number of required measurements for non-linear model generation, in comparison to the classical approach based on multi-bias broadband S-parameter measurements.