A set-up with load- and source-pull capabilities for phase noise and frequency stability characterization of microwave devices under oscillating operation

Phase noise (PN) performance of microwave oscillators can be strongly affected by the device non-linear RF working regime; indeed PN performance are related to the frequency stability of the circuit, which depends not only on the circuit Q factor, but also on the large-signal (LS) device operating condition. Besides the device operating bias point, also its dynamic LS load line and amplifying class of operation have a significant role for the oscillator PN. In this paper a very flexible measurement set-up is described with load and source pull capabilities, designed for the characterization of the PN and frequency stability of electron devices in controlled oscillating conditions. This innovative set-up is a very useful tool for both the design of low phase noise (LPN) oscillators and the parameter extraction and validation of non-linear noise models of electron devices.