A 83-W, 51% GaN HEMT Doherty power amplifier for 3.5-GHz-band LTE base stations

This paper presents a high-power, high-efficiency GaN HEMT Doherty power amplifier (DPA) for 3.5-GHz-band LTE macro-cell base-stations. To enhance the efficiency of the DPA, a new input matching circuit design based on a normalized peak amplifier's power ratio is proposed. A symmetrical DPA with the circuit is designed using 64.6% drain efficiency, 200W GaN HEMTs. The design shows significant improvement of both backed-off and peak efficiency of the DPA. At 3.51-GHz, high drain efficiency of 51.7% and 49.2 dBm (83 W) output power are achieved with a power gain of 13.5 dB and ACLR of -50.6 dBc using a LTE single carrier and digital predistortion system. This is the first demonstration of a GaN HEMT DPA of over 80W for 3.5-GHz-Band LTE macro-cell base-stations.