The impact of baseband electrical memory effects on the dynamic transfer characteristics of microwave power transistors

摘要

The inter-modulation distortion products can vary both in terms of amplitude and asymmetry due to the effects of baseband and 2^nd harmonic impedance. This paper presents an investigation into the relationship between the IMD asymmetries caused by baseband impedance variation and the looping or hysteresis that can sometimes appear in the dynamic transfer characteristics of microwave power devices when subjected to modulated excitation. The investigation is carried out using a 2W GaN HFET bare die device characterized at 2.1GHz, and using IF active load-pull to clarify the role of baseband impedance on observed hysteresis in the dynamic transfer characteristics. Analysis is performed using the envelope domain in order to more effectively reveal the DUT's sensitivity to impedance environments and specifically electrical baseband memory effects.