An S-Band GaN MMIC High Power Amplifier with 50W Output Power and 55% Power Added Efficiency

This paper presents the experimental results of a monolithic microwave integrated circuit (MMIC) high power amplifier (HPA) in Gallium Nitride (GaN) technology conceived for S- Band active electronically scanned array systems. The MMIC is based on a three-stage architecture and it is realized on a commercially available $\pmb{0.25\mu}\ \mathbf{mGaN}$ process. In order to maximize the efficiency and output power of the HPA, the harmonic terminations of the devices in the final stage were carefully optimized to actuate a class F working condition. Thanks to this, the MMIC is able to deliver an output power higher than 50W with an associated gain and power added efficiency greater than 36 dB and 55%, respectively, in a fractional bandwidth larger than 13% within the S-Band. Even if the HPA comprises three stages, the overall chip area is limited to $\pmb{6\text{x}5\ \text{mm}^{2}}$.