Impact on Linearity of a Wideband Design Strategy for an Integrated GaN Doherty Power Amplifier

This paper presents the design and linearity characterization of an integrated Doherty amplifier for 5G applications in the FR1 bands, implemented on a 150 nm GaN/SiC HEMT technology. It achieves 5G real-case-scenario performance over a 41% state-of-the-art fractional bandwidth, with 37 dBm saturated output power, 19 dB small-signal gain, and power-added efficiency above 20% over 6 dB back-off. The impact of the wideband combiner strategy on the linearity of the amplifier is analyzed in terms of baseband impedance and AM/PM. The characterization is then presented, with continuous wave and modulated signals for 100 MHz and 200 MHz instantaneous bandwidths. In presence of a 256-QAM 200 MHz input signal, the predistorted amplifier presents at 4.15 GHz an EVM of 2.9%.