A 6-18 GHz High-Efficiency GaN Power Amplifier Using Transistor Stacking and Reactive Matching

This article presents the design and implementation of a 6-18 GHz GaN monolithic microwave integrated circuit (MMIC) power amplifier (PA). A two-stage cascaded reactive matching network structure based on transistor stacking technology is employed to achieve circuit gain, and a multi-cell combination is used in the final stage to simultaneously achieve high power and high efficiency. For demonstration, a prototype of the proposed PA with an area of 4.5 × 3.4 mm² is fabricated in a 0.1 µm GaN-on-Si high-electron-mobility transistor (HEMT) process. The measured results of the GaN PA show a small signal gain of 25-29 dB, an output power of 40.8-42.5 dBm, and a power-added efficiency (PAE) of 27-38% in the operating frequency range of 6-18 GHz.