A Gallium Nitride (GaN) Doherty power amplifier chip design based on series RC stability network

This paper presents Doherty power amplifier (DPA) based on gallium nitride (GaN) technology, incorporating a parallel grounded network with series RC elements in front of the carrier and peaking amplifiers to enhance circuit stability. In comparison to the traditional series network with parallel RC structure, this configuration effectively reduces the sensitivity of the stability factor K to the capacitance value within the stability network. Consequently, it mitigates the impact on various performance indicators such as gain and drain efficiency, addressing the issue of measurement performance deviation caused by inaccurate capacitance models in the simulation files, which is particularly crucial for DPA. As a result, the circuit exhibits improved consistency in design and processing. With full band stability, the DPA achieves a saturation output power of approximately 29.8 dBm at 28 GHz, a saturation efficiency of 38.2%, and a 6-dB back-off efficiency of 29.6%. This research proposed a Doherty PA based on GaN technology, incorporating stability network with parallel grounded network with series RC. This structure reduces the sensitivity of circuits to capacitors in stability networks, alleviates the accuracy issues of capacitor models, and achieves 38.2% saturation efficiency and 29.6% 6-dB back-off efficiency at 28 GHz.image