Measurement of Memory Effect of High-Power Si LDMOSFET Amplifier Using Two-tone Phase Evaluation

We present a simple and straightforward method to accurately measure the relative phases of the fundamental and intermodulation components for a high power amplifier. The measurement is based on the cancellation between the low frequency signals from the down-converted amplifier output and reference signal generator. The cancellation principle, deembedding technique of the delay mismatch between the two path, and the accuracy and dynamic range for the measurements are also analyzed.