Active and hybrid harmonic load pull systems: An overview and comparison

This paper compares purely active and hybrid harmonic load pull systems. Purely active systems come in the form of closed active load or open active signal injection. Hybrid systems use active injection and impedance tuners to pre-match the injection power amplifier to the low transistor impedance. Harmonic tuning requires additional sources and/or harmonic tuners. Each approach is scrutinized based on technical and cost criteria.