Assets of source pull for NVNA based load pull measurements

This study deals with Vector Network Analyser based source-load-pull measurements. While a lot of papers demonstrated the influence of harmonic load impedances on PAE performances and time domain RF waveforms shaping, the harmonic source-pull topic has been a little bit less addressed. When using a traditional power meter based source/load-pull bench, source pull measurements are mandatory. Indeed, for a fixed power level and a given set of load impedances, the source pull optimization highlights the conditions to match the transistor's input access. Nowadays, modern Vector Network Analyser based source-load pull systems provide the direct measurements of the transistor input impedance. Thus, from the theoretical definition of any arbitrary source impedance, the mismatch calculus between input and source impedances is possible. It gives rise to a new kind of virtual source pull measurements. Some of us have called this method “magic source pull”. This method and its limitations will be explained, comparison between traditional source pull and Vector Network Analyser based “magic source pull” will be provided.