High-Power Time-Domain Measurement System with Active Harmonic Load--Pull for High-Efficiency Base-Station Amplifier Design

A measurement system combining vector corrected waveform measurements with active harmonic load--pull extends, for the first time, real-time experimental waveform engineering up to the 30-W power level. The vector correction procedure is presented in this paper. A novel harmonic load-pull approach based on the real-time measurement capability of the system is demonstrated on a 4-W LDMOS device. A 20% increase in maximum output power to 4.7 W without degrading gain and efficiency is realized. Waveform analysis at various drive and load conditions directly identifies nonlinear capacitance effects being a key design issue for the design of highly efficient power amplifier. Index Terms--Active load-pull, calibration, microwave measurements, microwave power amplifier, modeling, MOSFETs, nonlinearities, time-domain measurements.