Comparing Harmonic Load Pull Techniques With Regards to
As more demanding requirements emerge in wireless amplifier design, engineers have been forced to increase device output power while maintaining low current consumption. In achieving this goal, harmonic tuning has helped overcome efficiency requirements by reducing current consumption. Additionally, tuning harmonic impedances has proven to have a large effect on PAE, Pout, Gain and linearity when testing high power devices at compression. In this note we will compare the three most commonly used harmonic load pull methods: The triplexer method, Harmonic Rejection Tuner method and the Multi-Purpose tuner method. While different in many ways, these techniques should result in the maximum attainable PAE at the same phase of the impedances seen at the harmonic frequencies 2fo and 3fo, as long as they lay inside the tuning range of the corresponding technique.