A C-Band 20W GaN Power Amplifier MMIC and New Digital Predistortion Design

This paper describes the design of a C-band monolithic microwave integrated circuit (MMIC) high power amplifier (HPA) based on $0.25 \mu \mathrm{~m}$ GaN HEMT process. The circuit structure adopts a two-stage amplifier structure, and a synthesis matching network is used in the final stage to achieve twoway power synthesis. In addition, a new digital pre-distortion technique based on a real valued time-delay neural network (RVTDNN) architecture is proposed. Under the continuous wave test, the output power is more than $43 \mathrm{dBm}(20 \mathrm{~W})$ in $6.9-7.3 \mathrm{GHz}$, and the power added efficiency (PAE) is more than $47 \%$. Under the 10 MHz LTE signal test, the ACPR reaches ${- 4 5. 7} \mathrm{dBc}$ after digital pre-distortion, which further improves the linearity performance of the amplifier.