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

Area of Science:

• Electrical Engineering
• Materials Science
• Semiconductor Physics

Background:

• Gallium Nitride (GaN) High Electron Mobility Transistors (HEMTs) are crucial for high-frequency power amplification.
• Designing wideband power amplifiers (PAs) with simultaneous high power and efficiency remains a significant challenge.
• Monolithic Microwave Integrated Circuits (MMICs) offer miniaturization and improved performance for RF applications.

Purpose of the Study:

• To design and implement a wideband GaN MMIC power amplifier (PA) operating from 6-18 GHz.
• To achieve high output power and high power-added efficiency (PAE) over the specified frequency range.
• To demonstrate the effectiveness of transistor stacking and multi-cell combination techniques in PA design.

Main Methods:

• Utilized a two-stage cascaded reactive matching network structure.
• Employed transistor stacking technology to enhance circuit gain.
• Implemented a multi-cell combination in the final stage for high power and efficiency.
• Fabricated a prototype GaN MMIC PA using a 0.1 µm GaN-on-Si HEMT process.

Main Results:

• Achieved a small signal gain ranging from 25-29 dB across the 6-18 GHz band.
• Delivered an output power between 40.8-42.5 dBm.
• Obtained a power-added efficiency (PAE) of 27-38% within the operating frequency range.
• The fabricated prototype measured 4.5 × 3.4 mm².

Conclusions:

• The designed GaN MMIC PA effectively meets the 6-18 GHz wideband requirements.
• The employed design techniques successfully achieved high power and high efficiency simultaneously.
• The results validate the potential of GaN-on-Si HEMT technology for advanced RF power amplifier applications.