A fully calibrated four channels time domain RF envelope measurement system for the envelope characterization of nonlinear devices in a load-pull environment

This paper presents a fully calibrated four channels time domain radio-frequency (RF) envelope characterization system. This measurement system enables the acquisition and the vector-correction of the 4 input and output envelope voltage/current waves, including both amplitude and phase, of RF nonlinear microwave devices. The capabilities of the system, when it is associated with passive load pull techniques, are presented to investigate the effects of RF impedance termination on the envelope linearity of mismatched RF nonlinear devices. The proposed measurement set-up is described. Calibration and measurement procedures are detailed. Examples of the 4 fully error corrected time domain envelopes at the input/output RF ports of an optimised gain power MESFET are reported and discussed.