An Efficiency and Size Optimized 2GHz 25W Cascaded Doherty RF Power Amplifiers Using GAN HEMTs

Abstract

NEC has developed a 2.1GHz band very compact and high efficiency power amplifier module based on GaN HEMT cascaded Doherty circuitry. Implemented modules exhibits the amplifier chain power added efficiency of 45% and the final stage drain efficiency of 58% at 25W output level with associated gain of 44dB. The module works well with DPD to achieve -51dBc ACLR using an LTE E-TM1.1 signal with the peak-to-average-power-ratio of 7.1dB. The module occupies only 99cm2. Compact driver stage Doherty circuitry implemented on the multi-layer composite materials PCB contributes both to efficiency enhancement and shrunk foot print.