Design of class E power amplifiers by using scalable electro-thermal GaN HEMT model

Abstract

In this paper, a scalable large signal GaN HEMT model including nonlinear thermal sub-circuit is described. Only two scalable parameters are needed in the I_ds scalable model by introducing a simple correction factor. The established model can predict the I–V curves at different-in-size AlGaN/GaN HEMTs devices accurately. Small signal S-parameters and large signal load pull tests with on-wafer measurement is used to further validate the proposed model. Finally, the proposed scalable model is used to design a broadband high efficiency continuous class-E power amplifier (PA). Experimental results show that this class E PA is realized from 2.5–3.5 GHz with drain efficiency of 60%–70%, over 8.2 dB gain and over 35.2 dBm output by using a GaN HEMT with 1.25 mm total gate width. The results show that the proposed model is useful for high efficiency amplifier design.