New Patent: Harmonic Active Injection Load Pull

Focus has received today notice of allowance of a new US patent on Hybrid Active Harmonic Load Pull technology.

In 15 claims a multitude of hybrid load pull configurations are described, including wideband and harmonic tuners and tuner cascades, circulators and couplers/triplexers as well as two, three or four synchronized harmonic signal sources. 


Filed 10 March 2010


A method and test setup for reducing the RF power requirement in active load pull uses impedance tuners between the output of the test transistor and the active RF power injection network. The active network uses either a closed loop (active load) configuration or an open loop network employing split or synchronized signal sources. The impedance tuners are wideband (fundamental) tuners, harmonic rejection tuners or multi-harmonic tuners. A 7:1 transforming ratio of the tuners represents the best compromise between power matching and tuner loss, yielding a reduction of 11dB in power requirements from the active load or the synchronized source(s); if only the fundamental signal is injected at the output of the DUT, a multi-harmonic tuner or a harmonic rejection tuner is used for independent harmonic tuning; if multiple harmonic signals are injected, a multi-harmonic tuner is used and creates passive harmonic loads while reducing at the same time the power requirements from the harmonic injection sources.