A novel load-pull setup with envelope calibration for bias modulated measurements

In this paper a measurement system for evaluation of RF-Power transistors in high-efficiency operation using drain bias-modulation is presented. The system is based on a novel 2-tone load-pull measurements configuration with envelope synchronized dynamic bias modulation. For the bias modulation a dynamic power analyzer for DC-low frequency power source and monitoring is used. A predicted 10–15 % efficiency enhancement in the backed of region for the studied LDMOS has been verified with the narrow bandwidth system. System calibration includes a general peak-power envelope synchronization method that is possible to use also in wider bandwidth systems.