A Fully Integrated 3.2-4.7GHz Doherty Power Amplifier in 300mm GaN-on-Si Technology

This paper presents the design and characterization of a fully integrated wide band Doherty power amplifier (PA) in 300mm GaN-on-Si technology employing CMOS-like PDK, design rules and design methodology. A new Doherty PA architecture using the stacked transistor configuration with equal voltage distribution is implemented in the auxiliary path to improve performance and power utilization factor. A lumped element based Doherty combiner is designed to maximize the bandwidth and to enhance the back-off efficiency. A wide band lumped element based quadrature coupler is also implemented on-chip. This compact Doherty PA (small core area of 1.66mm
²
) achieves a 1-dB fractional bandwidth of 38% (3.2-4.7GHz) with over 39% efficiency at 6dB power back-off. This is the first demonstration of Watt level RF power amplifier in 300mm GaN-on-Si technology.