A High Efficiency 4–18 GHz GaN MMIC Power Amplifier based on 90nm T-gate GaN HEMT Technology

This paper describes the design and measured performance of a wideband power amplifier MMIC based on Qorvo's 90nm T-gate GaN HEMT technology. This GaN technology is characterized by a peak fT of 145 GHz, a PAE > 55%, and a P3dB output power density> 2.0W/mm at 35 GHz. The amplifier design utilizes the non-uniform distributed power amplifier (NDPA) architecture with an wideband edge coupling 1:4 output transformer to achieve high efficiency and power. This single-stage NDPA produces 3 – 5.3 W of output power over the 4 – 18 GHz band with a PAE of 25.6 – 35.7% at 13 V supply voltage. The large-signal gain varies between 7.7 dB at the low band edge and 10.2dB in most of the band. Meanwhile, the NDPA has achieved a small-signal gain of 12.0 – 14.5 dB over the same band. Additionally, 5.6 – 7.0 W of output power with 21–34.2% of PAE has been measured up to 18 V supply voltage. Based on the advantages of the 90nm GaN T-gate HEMT technology, the design has established new benchmarks of efficiency for PAs operating at similar band compared to other state-of-the-art GaN NDPAs.