Recent progress and future prospects of GaN HEMTs for base-station applications

This paper describes the recent progress and future prospects of GaN high electron mobility transistors (HEMTs) for 3G-wireless base station applications. It introduces a summary of most important activities at several organizations all over the world. As the Fujitsu progress, a state-of-the-art 250-W AlGaN/GaN-HEMTs push-pull transmitter amplifier operated at a drain bias voltage of 50 V is addressed. The amplifier, combined with a digital pre-distortion (DPD) system, also achieved an adjacent channel leakage power ratio (ACLR) of less than -50 dBc for 4-carrier W-CDMA signals with a drain supply voltage of 50 V. This paper also demonstrates a stable operation under RF stress testing for 1000 h at a drain bias voltage of 60 V. After comparing LDMOS, GaAs and GaN, future prospects of GaN-HEMT is discussed to verify that an AlGaN/GaN HEMTs amplifier is suitable for 3G W-CDMA systems.