A harmonic load pull system uses a number of synchronized signal sources to inject harmonic power into the output of a power transistor. The mismatch between the signal sources and the transistor internal impedance is reduced by using multi-harmonic tuners, which pre-match the impedance of the signal sources to the internal impedance of the transistor at each harmonic frequency independently. Actual tuning is electronic by changing the amplitude and phase of the injected signals. The transmitted and reflected waves are measured and optimized through bi-directional couplers connected between the transistor and the tuner and a wideband harmonic receiver.
Multi-Source Active Injection Load Pull System and Method / 9,213,056
Tuesday, December 15, 2015